Adjust heading depths

README.md

     - [PHP Internals Reading](#php-internals-reading)
 - [Contributing](#contributing)
 
-## Composer Repositories
+### Composer Repositories
 *Composer Repositories.*
 
 * [Firegento](http://packages.firegento.com/) - Magento Module Composer Repository.
 * [WordPress Packagist](https://wpackagist.org/) - Manage your plugins with Composer.
 * [Zend Framework Packages](https://packages.zendframework.com/) - Zend Framework Composer Repository.
 
-## Dependency Management
+### Dependency Management
 *Libraries for dependency and package management.*
 
 * [Composer Installers](https://github.com/composer/installers) - A  multi framework Composer library installer.
 * [Melody](http://melody.sensiolabs.org/) - A tool to build one file Composer scripts.
 * [Pickle](https://github.com/FriendsOfPHP/pickle) - A PHP extension installer.
 
-## Dependency Management Extras
+### Dependency Management Extras
 *Extras related to dependency management.*
 
 * [Composed](https://github.com/joshdifabio/composed) - A library to parse your project's Composer environment at runtime.
 * [tooly](https://github.com/tommy-muehle/tooly-composer-script) - A library to manage PHAR files in project using Composer.
 * [Toran Proxy](https://toranproxy.com) - A static Composer repository and proxy.
 
-## Frameworks
+### Frameworks
 *Web development frameworks.*
 
 * [Aura Framework](http://auraphp.com/framework/) - A framework built from independent components.
 * [Zend Framework 2](https://framework.zend.com) - Another framework comprised of individual components (ZF2).
 * [Ice](https://www.iceframework.org/) - Another simple and fast PHP framework delivered as C-extension.
 
-## Framework Extras
+### Framework Extras
 *Extras related to web development frameworks.*
 
 * [CakePHP CRUD](https://github.com/friendsofcake/crud) - A Rapid Application Development (RAD) plugin for CakePHP.
 * [Knp RAD Components](http://rad.knplabs.com/) - A set of Rapid Application Development (RAD) components for Symfony.
 * [Symfony CMF](https://github.com/symfony-cmf/symfony-cmf) - A Content Management Framework to create custom CMS.
 
-## Components
+### Components
 *Standalone components from web development frameworks and development groups.*
 
 * [Aura](http://auraphp.com/) - Independent components, fully decoupled from each other and from any framework.
 * [Symfony Components](http://symfony.com/doc/master/components/index.html) - The components that make Symfony.
 * [Zend Framework 2 Components](https://docs.zendframework.com/) - The components that make Zend Framework.
 
-## Micro Frameworks
+### Micro Frameworks
 *Micro frameworks and routers.*
 
 * [Bullet PHP](http://bulletphp.com/) - A micro framework for building REST APIs.
 * [Silex](https://silex.symfony.com/) - A micro framework built around Symfony components.
 * [Slim](https://www.slimframework.com/) - Another simple micro framework.
 
-## Micro Framework Extras
+### Micro Framework Extras
 *Extras related to micro frameworks and routers.*
 
 * [Silex Skeleton](https://github.com/silexphp/Silex-Skeleton) - A project skeleton for Silex.
 * [Slim Skeleton](https://github.com/slimphp/Slim-Skeleton) - A skeleton for Slim.
 * [Slim View](https://github.com/slimphp/Slim-Views) - A collection of custom views for Slim.
 
-## Routers
+### Routers
 *Libraries for handling application routing.*
 
 * [Aura.Router](https://github.com/auraphp/Aura.Router) - A full-featured routing library.
 * [Pux](https://github.com/c9s/Pux) - Another fast routing library.
 * [Route](https://github.com/thephpleague/route) - A routing library built on top of Fast Route.
 
-## Templating
+### Templating
 *Libraries and tools for templating and lexing.*
 
 * [Aura.View](https://github.com/auraphp/Aura.View) - Provides TemplateView and TwoStepView using PHP as the tempting language, with support for partials, sections, and helpers.
 * [Twig](https://twig.symfony.com/) - A comprehensive templating language.
 * [Tale Jade](https://github.com/Talesoft/tale-jade) - A PHP implementation of the Jade template language.
 
-## Static Site Generators
+### Static Site Generators
 *Tools for pre-processing content to generate web pages.*
 
 * [Couscous](http://couscous.io) - Couscous turns Markdown documentation into beautiful websites. It's GitHub Pages on steroids.
 * [Sculpin](https://sculpin.io) - A tool that converts Markdown and Twig into static HTML.
 * [Spress](http://spress.yosymfony.com) - An extensible tool that converts Markdown and Twig into HTML.
 
-## HTTP
+### HTTP
 *Libraries for working with HTTP.*
 
 * [Buzz](https://github.com/kriswallsmith/Buzz) - Another HTTP client.
 * [Retrofit](https://github.com/tebru/retrofit-php) - A library to ease creation of REST API clients.
 * [zend-diactoros](https://github.com/zendframework/zend-diactoros) - PSR-7 HTTP Message implementation.
 
-## Scraping
+### Scraping
 *Libraries for scraping websites.*
 
 * [Embed](https://github.com/oscarotero/Embed) - An information extractor from any web service or page.
 * [Goutte](https://github.com/FriendsOfPHP/Goutte) - A simple web scraper.
 * [PHP Spider](https://github.com/mvdbos/php-spider) - A configurable and extensible PHP web spider.
 
-## Middlewares
+### Middlewares
 *Libraries for building application using middlewares.*
 
 * [Expressive](https://zendframework.github.io/zend-expressive/) - PSR-7 Middleware framework from Zend.
 * [Stack](https://github.com/stackphp) - A library of stackable middleware for Silex/Symfony.
 * [zend-stratigility](https://github.com/zendframework/zend-stratigility) - Middleware for PHP built on top of PSR-7.
 
-## URL
+### URL
 *Libraries for parsing URLs.*
 
 * [PHP Domain Parser](https://github.com/jeremykendall/php-domain-parser) - A domain suffix parser library.
 * [sabre/uri](https://github.com/sabre-io/uri) - A functional URI manipulation library.
 * [Uri](https://github.com/thephpleague/uri) - Another URL manipulation library.
 
-## Email
+### Email
 *Libraries for sending and parsing email.*
 
 * [CssToInlineStyles](https://github.com/tijsverkoyen/CssToInlineStyles) - A library to inline CSS in email templates.
 * [Stampie](https://github.com/Stampie/Stampie) - A library for email services such as [SendGrid](https://sendgrid.com/), [PostMark](https://postmarkapp.com), [MailGun](https://www.mailgun.com/) and [Mandrill](http://www.mandrill.com).
 * [SwiftMailer](https://swiftmailer.symfony.com) - A mailer solution.
 
-## Files
+### Files
 *Libraries for file manipulation and MIME type detection.*
 
 * [Apache MIME Types](https://github.com/dflydev/dflydev-apache-mime-types) - A library that parses Apache MIME types.
 * [PHP FFmpeg](https://github.com/PHP-FFmpeg/PHP-FFmpeg/) - A wrapper for the [FFmpeg](http://www.ffmpeg.org/) video library.
 * [UnifiedArchive](https://github.com/wapmorgan/UnifiedArchive) - A unified reader and writer of compressed archives.
 
-## Streams
+### Streams
 *Libraries for working with streams.*
 
 * [Streamer](https://github.com/fzaninotto/Streamer) - A simple object-orientated stream wrapper library.
 
-## Dependency Injection
+### Dependency Injection
 *Libraries that implement the dependency injection design pattern.*
 
 * [Aura.Di](https://github.com/auraphp/Aura.Di) - A serializable dependency injection container with constructor and setter injection, interface and trait awareness, configuration inheritance, and much more.
 * [Pimple](https://pimple.symfony.com/) - A tiny dependency injection container.
 * [Symfony DI](https://github.com/symfony/dependency-injection) - A dependency injection container component (SF).
 
-## Imagery
+### Imagery
 *Libraries for manipulating images.*
 
 * [Color Extractor](https://github.com/thephpleague/color-extractor) - A library for extracting colours from images.
 * [Intervention Image](https://github.com/Intervention/image) - Another image manipulation library.
 * [PHP Image Workshop](https://github.com/Sybio/ImageWorkshop) - Another image manipulation library.
 
-## Testing
+### Testing
 *Libraries for testing codebases and generating test data.*
 
 * [Alice](https://github.com/nelmio/alice) - An expressive fixture generation library.
 * [VFS Stream](https://github.com/mikey179/vfsStream) - A virtual filesystem stream wrapper for testing.
 * [VFS](https://github.com/adlawson/php-vfs) - Another virtual filesystem for testing.
 
-## Continuous Integration
+### Continuous Integration
 *Libraries and applications for continuous integration.*
 
 * [CircleCI](https://circleci.com) - A continuous integration platform.
 * [Travis CI](https://travis-ci.org/) - A continuous integration platform.
 * [Wercker](http://www.wercker.com/) - A continuous integration platform
 
-## Documentation
+### Documentation
 *Libraries for generating project documentation.*
 
 * [APIGen](https://github.com/apigen/apigen) - Another API documentation generator.
 * [phpDox](http://phpdox.de/) - A documentation generator for PHP projects (that is not limited to API documentation).
 * [Sami](https://github.com/FriendsOfPHP/Sami) - An API documentation generator.
 
-## Security
+### Security
 *Libraries for generating secure random numbers, encrypting data and scanning for vulnerabilities.*
 
 * [Halite](https://paragonie.com/project/halite) - A simple library for encryption using [libsodium](https://github.com/jedisct1/libsodium).
 * [VAddy](https://vaddy.net/) - A continuous security testing platform for web applications.
 * [Zed](https://www.owasp.org/index.php/OWASP_Zed_Attack_Proxy_Project) - An integrated penetration testing tool for web applications.
 
-## Passwords
+### Passwords
 *Libraries and tools for working with and storing passwords.*
 
 * [GenPhrase](https://github.com/timoh6/GenPhrase) - A library for generating secure random passphrases.
 * [phpass](http://www.openwall.com/phpass/) - A portable password hashing framework.
 * [Zxcvbn PHP](https://github.com/bjeavons/zxcvbn-php) - A realistic PHP password strength estimate library based on Zxcvbn JS.
 
-## Code Analysis
+### Code Analysis
 *Libraries and tools for analysing, parsing and manipulating codebases.*
 
 * [Better Reflection](https://github.com/Roave/BetterReflection) - AST-based reflection library that allows analysis and manipulation of code
 * [Scrutinizer](https://scrutinizer-ci.com/) - A web tool to [scrutinise PHP code](https://github.com/scrutinizer-ci/php-analyzer).
 * [UBench](https://github.com/devster/ubench) - A simple micro benchmark library.
 
-## Code Quality
+### Code Quality
 *Libraries for managing code quality, formatting and linting.*
 
 * [PHP CodeSniffer](https://github.com/squizlabs/PHP_CodeSniffer) - A library that detects PHP, CSS and JS coding standard violations.
 * [PHPCheckstyle](https://github.com/PHPCheckstyle/phpcheckstyle) - A tool to help adhere to certain coding conventions.
 * [PHPCPD](https://github.com/sebastianbergmann/phpcpd) - A library that detects copied and pasted code.
 
-## Static Analysis
+### Static Analysis
 *Libraries for performing static analysis of PHP code.*
 
 * [Exakat](https://github.com/exakat/exakat) - A static analysis engine for PHP.
 * [PHPStan](https://github.com/phpstan/phpstan) - A PHP Static Analysis Tool.
 * [Pslam](https://github.com/vimeo/psalm) - A static analysis tool for finding errors in PHP applications.
 
-## Architectural
+### Architectural
 *Libraries related to design patterns, programming approaches and ways to organize code.*
 
 * [Compose](https://github.com/igorw/compose) - A function composition library.
 * [Ruler](https://github.com/bobthecow/Ruler) - A simple stateless production rules engine.
 * [RulerZ](https://github.com/K-Phoen/rulerz) - A powerful rule engine and implementation of the Specification pattern.
 
-## Debugging and Profiling
+### Debugging and Profiling
 *Libraries and tools for debugging and profiling code.*
 
 * [APM](http://pecl.php.net/package/APM) - Monitoring extension collecting errors and statistics into SQLite/MySQL/StatsD.
 * [XHProf](https://github.com/phacility/xhprof) - A profiling tool originally developed by Facebook.
 * [Z-Ray](http://www.zend.com/en/products/server/z-ray) - A debug and profile tool for Zend Server.
 
-## Build Tools
+### Build Tools
 *Project build and automation tools.*
 
 * [Bob](https://github.com/CHH/bob) - A simple project automation tool.
 * [Phake](https://github.com/jaz303/phake) - A rake PHP clone library.
 * [Phing](https://www.phing.info/) - A PHP project build system inspired by Apache Ant.
 
-## Task Runners
+### Task Runners
 *Libraries for automating and running tasks.*
 
 * [Bldr](http://bldr.io/) - A PHP Task runner built on Symfony components.
 * [Robo](https://github.com/consolidation/Robo) - A PHP Task runner with object-orientated configurations.
 * [Task](http://taskphp.github.io/) - A pure PHP task runner inspired by Grunt and Gulp.
 
-## Navigation
+### Navigation
 *Tools for building navigation structures.*
 
 * [KnpMenu](https://github.com/KnpLabs/KnpMenu) - A menu library.
 
-## Asset Management
+### Asset Management
 *Tools for managing, compressing and minifying website assets.*
 
 * [JShrink](https://github.com/tedious/JShrink) - A JavaScript minifier library.
 * [Puli](https://github.com/puli/repository) - A library for determining assets absolute paths.
 * [BowerPHP](https://github.com/Bee-Lab/bowerphp) - A PHP implementation of Bower. A package manager for the web
 
-## Geolocation
+### Geolocation
 *Libraries for geocoding addresses and working with latitudes and longitudes.*
 
 * [GeoCoder](http://geocoder-php.org/) - A geocoding library.
 * [GeoTools](https://github.com/thephpleague/geotools) - A library of geo-related tools.
 * [PHPGeo](https://github.com/mjaschen/phpgeo) - A simple geo library.
 
-## Date and Time
+### Date and Time
 *Libraries for working with dates and times.*
 
 * [CalendR](http://yohan.giarel.li/CalendR/) - A calendar management library.
 * [Moment.php](https://github.com/fightbulc/moment.php) - Moment.js inspired PHP DateTime handler with i18n support.
 * [Yasumi](https://github.com/azuyalabs/yasumi) - An library to help you calculate the dates and names of holidays.
 
-## Event
+### Event
 *Libraries that are event-driven or implement non-blocking event loops.*
 
 * [Amp](https://github.com/amphp/amp) - An event driven non-blocking I/O library.
 * [Rx.PHP](https://github.com/asm89/Rx.PHP) - A reactive extension library.
 * [Workerman](https://github.com/walkor/Workerman) - An event driven non-blocking I/O library.
 
-## Logging
+### Logging
 *Libraries for generating and working with log files.*
 
 * [Monolog](https://github.com/Seldaek/monolog) - A comprehensive logger.
 
-## E-commerce
+### E-commerce
 *Libraries and applications for taking payments and building online e-commerce stores.*
 
 * [Money](https://github.com/moneyphp/money) - A PHP implementation of Fowler's money pattern.
 * [Swap](https://github.com/florianv/swap) - An exchange rates library.
 * [Sylius](http://sylius.org/) - An open source e-commerce solution.
 
-## PDF
+### PDF
 *Libraries and software for working with PDF files.*
 
 * [Dompdf](https://github.com/dompdf/dompdf) - A HTML to PDF converter.
 * [Snappy](https://github.com/KnpLabs/snappy) - A PDF and image generation library.
 * [WKHTMLToPDF](https://github.com/wkhtmltopdf/wkhtmltopdf) - A tool to convert HTML to PDF.
 
-## Office
+### Office
 *Libraries for working with office suite documents.*
 
 * [ExcelAnt](https://github.com/Wisembly/ExcelAnt) - A library for manipulating Microsoft Excel documents.
 * [PHPWord](https://github.com/PHPOffice/PHPWord) - A library for working with Microsoft Word documents.
 * [PHPSpreadsheet](https://github.com/PHPOffice/PhpSpreadsheet) - A pure PHP library for reading and writing spreadsheet files (successor of PHPExcel)
 
-## Database
+### Database
 *Libraries for interacting with databases using object-relational mapping (ORM) or datamapping techniques.*
 
 * [Atlas.Orm](https://github.com/atlasphp/Atlas.Orm) - A data mapper implementation for your persistence model in PHP.
 * [RedBean](https://redbeanphp.com/index.php) - A lightweight, configuration-less ORM.
 * [Spot2](https://github.com/spotorm/spot2) - A MySQL datamapper ORM.
 
-## Migrations
+### Migrations
 Libraries to help manage database schemas and migrations.
 
 * [Doctrine Migrations](http://docs.doctrine-project.org/projects/doctrine-migrations/en/latest/toc.html) - A migration library for Doctrine.
 * [PHPMig](https://github.com/davedevelopment/phpmig) - Another migration management library.
 * [Ruckusing](https://github.com/ruckus/ruckusing-migrations) - Database migrations for PHP ala ActiveRecord Migrations with support for MySQL, Postgres, SQLite.
 
-## NoSQL
+### NoSQL
 *Libraries for working with "NoSQL" backends.*
 
 * [Monga](https://github.com/thephpleague/monga) - A MongoDB abstraction library.
 * [PHPMongo](https://github.com/sokil/php-mongo) - A MongoDB ORM.
 * [Predis](https://github.com/nrk/predis) - A feature complete Redis library.
 
-## Queue
+### Queue
 *Libraries for working with event and task queues.*
 
 * [Bernard](https://github.com/bernardphp/bernard) - A multibackend abstraction library.
 * [Tarantool Queue](https://github.com/tarantool-php/queue) - PHP bindings for Tarantool Queue.
 * [Thumper](https://github.com/php-amqplib/Thumper) - A RabbitMQ pattern library.
 
-## Search
+### Search
 *Libraries and software for indexing and performing search queries on data.*
 
 * [Elastica](https://github.com/ruflin/Elastica) - A client library for ElasticSearch.
 * [Sphinx Search](https://github.com/ripaclub/sphinxsearch) - Sphinx Search library provides SphinxQL indexing and searching features
 * [SphinxQL query builder](http://foolcode.github.io/SphinxQL-Query-Builder/) - A query library for the [Sphinx](http://sphinxsearch.com/) search engine.
 
-## Command Line
+### Command Line
 *Libraries related to the command line.*
 
 * [Aura.Cli](https://github.com/auraphp/Aura.Cli) - Provides the equivalent of request ( Context ) and response ( Stdio ) objects for the command line interface, including Getopt support, and an independent Help object for describing commands.
 * [PsySH](https://github.com/bobthecow/psysh) - Another PHP REPL.
 * [ShellWrap](https://github.com/MrRio/shellwrap) - A simple command line wrapper library.
 
-## Authentication and Authorization
+### Authentication and Authorization
 *Libraries for implementing user authentication and authorization.*
 
 * [Aura.Auth](https://github.com/auraphp/Aura.Auth) - Provides authentication functionality and session tracking using various adapters.
 * [TwitterOAuth](https://github.com/abraham/twitteroauth) - A Twitter OAuth library.
 * [TwitterSDK](https://github.com/lyrixx/twitter-sdk) - A fully tested Twitter SDK.
 
-## Markup
+### Markup
 *Libraries for working with markup.*
 
 * [Cebe Markdown](https://github.com/cebe/markdown) - An fast and extensible Markdown parser.
 * [Parsedown](https://github.com/erusev/parsedown) - Another Markdown parser.
 * [PHP Markdown](https://github.com/michelf/php-markdown) - A Markdown parser.
 
-## Strings
+### Strings
 *Libraries for parsing and manipulating strings.*
 
 * [Agent](https://github.com/jenssegers/agent) - A PHP desktop/mobile user agent parser, based on Mobiledetect.
 * [URLify](https://github.com/jbroadway/urlify) - A PHP port of Django's URLify.js.
 * [UUID](https://github.com/ramsey/uuid) - A library for generating UUIDs.
 
-## Numbers
+### Numbers
 *Libraries for working with numbers.*
 
 * [ByteUnits](https://github.com/gabrielelana/byte-units) - A library to parse, format and convert byte units in binary and metric systems.
 * [PHP Conversion](https://github.com/Crisu83/php-conversion) - Another library for converting between units of measure.
 * [PHP Units of Measure](https://github.com/triplepoint/php-units-of-measure) - A library for converting between units of measure.
 
-## Filtering and Validation
+### Filtering and Validation
 *Libraries for filtering and validating data.*
 
 * [Aura.Filter](https://github.com/auraphp/Aura.Filter) - Provides tools to validate and sanitize objects and arrays.
 * [Valitron](https://github.com/vlucas/valitron) - Another validation library.
 * [Volan](https://github.com/serkin/Volan) - Another simplified validation library.
 
-## API
+### API
 *Libraries and web tools for developing APIs.*
 
 * [API Platform](https://api-platform.com ) - Expose in minutes an hypermedia REST API that embraces JSON-LD, Hydra format.
 * [Restler](https://github.com/Luracast/Restler) - A lightweight framework to expose PHP methods as RESTful web API.
 * [wsdl2phpgenerator](https://github.com/wsdl2phpgenerator/wsdl2phpgenerator) - A tool to generate PHP classes from SOAP WSDL files.
 
-## Caching
+### Caching
 *Libraries for caching data.*
 
 * [Alternative PHP Cache (APC)](http://php.net/manual/en/book.apc.php) - Open opcode cache for PHP.
 * [Stash](https://github.com/tedious/Stash) - Another library for caching.
 * [Zend Cache](https://github.com/zendframework/zend-cache) - Another caching library (ZF2).
 
-## Data Structure and Storage
+### Data Structure and Storage
 *Libraries that implement data structure or storage techniques.*
 
 * [Ardent](https://github.com/morrisonlevi/Ardent) - A library of data structures.
 * [YaLinqo](https://github.com/Athari/YaLinqo) - Yet Another LINQ to Objects for PHP.
 * [Zend Serializer](https://github.com/zendframework/zend-serializer) - Another library for serialising and de-serialising data (ZF2).
 
-## Notifications
+### Notifications
 *Libraries for working with notification software.*
 
 * [JoliNotif](https://github.com/jolicode/JoliNotif) - A cross-platform library for desktop notification (support for Growl, notify-send, toaster, etc)
 * [Notificator](https://github.com/namshi/notificator) - A lightweight notification library.
 * [Php-pushwoosh](https://github.com/gomoob/php-pushwoosh) - A PHP Library to easily send push notifications with the Pushwoosh REST Web Services.
 
-## Deployment
+### Deployment
 *Libraries for project deployment.*
 
 * [Deployer](https://github.com/deployphp/deployer) - A deployment tool.
 * [Pomander](https://github.com/tamagokun/pomander) - A deployment tool for PHP applications.
 * [Rocketeer](https://github.com/rocketeers/rocketeer) - A fast and easy deployer for the PHP world.
 
-## Internationalisation and Localisation
+### Internationalisation and Localisation
 *Libraries for Internationalization (I18n) and Localization (L10n).*
 
 * [Aura.Intl](https://github.com/auraphp/Aura.Intl) - Provides internationalization (I18N) tools, specifically package-oriented per-locale message translation.
 * [Cake I18n](https://github.com/cakephp/i18n) - Message translation and localization for dates and numbers (CP)
 
-## Third Party APIs
+### Third Party APIs
 *Libraries for accessing third party APIs.*
 
 * [Amazon Web Service SDK](https://github.com/aws/aws-sdk-php) - The official PHP AWS SDK library.
 * [Twitter OAuth](https://github.com/widop/twitter-oauth) - A library to interface with Twitter's OAuth workflow.
 * [Twitter REST](https://github.com/widop/twitter-rest) - A library to interact with Twitter's REST API.
 
-## Extensions
+### Extensions
 *Libraries to help build PHP extensions.*
 
 * [PHP CPP](http://www.php-cpp.com/) - A C++ library for developing PHP extensions.
 * [Zephir](https://github.com/phalcon/zephir) - A compiled language between PHP and C++ for developing PHP extensions.
 
-## Miscellaneous
+### Miscellaneous
 *Useful libraries or tools that don't fit in the categories above.*
 
 * [Annotations](https://github.com/doctrine/annotations) - An annotations library (part of Doctrine).
 # Software
 *Software for creating a development environment.*
 
-## PHP Installation
+### PHP Installation
 *Tools to help install and manage PHP on your computer.*
 
 * [HomeBrew PHP](https://github.com/Homebrew/homebrew-php) - A PHP tap for HomeBrew.
 * [PHP Switch](https://github.com/jubianchi/phpswitch) - Another version manager.
 * [VirtPHP](http://virtphp.org/) - A tool for creating and managing isolated PHP environments.
 
-## Development Environment
+### Development Environment
 *Software and tools for creating a sandboxed development environment.*
 
 * [Ansible](https://www.ansible.com/) - A radically simple orchestration framework.
 * [Vagrant](https://www.vagrantup.com/) - A portable development environment utility.
 * [Docker](https://www.docker.com/) - A containerization platform.
 
-## Virtual Machines
+### Virtual Machines
 *Alternative PHP virtual machines.*
 
 * [Hack](http://hacklang.org/) - A programming language for HHVM that interoperates seamlessly with PHP.
 * [HHVM](https://github.com/facebook/hhvm) - A Virtual Machine, Runtime and JIT for PHP by Facebook.
 * [HippyVM](https://github.com/hippyvm/hippyvm) - Another PHP virtual machine.
 
-## Text Editors and IDEs
+### Text Editors and IDEs
 *Text Editors and Integrated Development Environments (IDE) with support for PHP.*
 
 * [Atom](https://atom.io/) - A hackable text editor.
 * [PhpStorm](http://www.jetbrains.com/phpstorm/) - A commercial PHP IDE.
 * [VS Code](https://code.visualstudio.com/) - An open source code editor.
 
-## Web Applications
+### Web Applications
 *Web-based applications and tools.*
 
 * [3V4L](https://3v4l.org/) - An online PHP & HHVM shell.
 * [Grav](https://github.com/getgrav/grav) - A modern flat-file CMS.
 * [Lychee](https://github.com/electerious/Lychee) - An easy to use and great looking photo-management-system.
 
-## Infrastructure
+### Infrastructure
 *Infrastructure for providing PHP applications and services.*
 
 * [appserver.io](https://appserver.io/) - A multithreaded application server for PHP, written in PHP.
 # Resources
 Various resources, such as books, websites and articles, for improving your PHP development skills and knowledge.
 
-## PHP Websites
+### PHP Websites
 *Useful PHP-related websites.*
 
 * [Nomad PHP](https://nomadphp.com/) - A online PHP learning resource.
 * [Seven PHP](https://7php.com/) - A website that interviews members of the PHP community.
 * [PHP Annotated Monthly](https://blog.jetbrains.com/phpstorm/category/php-annotated-monthly/) - A monthly digest of PHP news.
 
-## Other Websites
+### Other Websites
 *Useful websites related to web development.*
 
 * [Atlassian Git Tutorials](https://www.atlassian.com/git) - A series of Git tutorials.
 * [The Open Web Application Security Project (OWASP)](https://www.owasp.org/index.php/Main_Page) - An open software security community.
 * [WebSec IO](https://websec.io/) - A web security community resource.
 
-## PHP Books
+### PHP Books
 *Fantastic PHP-related books.*
 
 * [Functional Programming in PHP](https://www.functionalphp.com/) - This book will show you how to leverage these new PHP5.3+ features by understanding functional programming principles
 * [XML Parsing with PHP](https://www.phparch.com/books/xml-parsing-with-php/) - This book covers parsing and validating XML documents, leveraging XPath expressions, and working with namespaces as well as how to create and modify XML files programmatically.
 * [Domain-Driven Design in PHP](https://leanpub.com/ddd-in-php) - Real examples written in PHP showcasing DDD Architectural Styles.
 
-## Other Books
+### Other Books
 *Books related to general computing and web development.*
 
 * [Elasticsearch: The Definitive Guide](https://www.elastic.co/guide/index.html) - A guide to working with Elasticsearch by Clinton Gormley and Zachary Tong.
 * [Understanding Computation](http://computationbook.com) - A book about computation theory by Tom Stuart.
 * [Vagrant Cookbook](https://leanpub.com/vagrantcookbook) - A book about creating Vagrant environments by Erika Heidi.
 
-## PHP Videos
+### PHP Videos
 *Fantastic PHP-related videos.*
 
 * [Nomad PHP Lightning Talks](https://www.youtube.com/c/nomadphp) - 10 to 15 minute Lightning Talks by PHP community members.
 * [Programming with Anthony](https://www.youtube.com/playlist?list=PLM-218uGSX3DQ3KsB5NJnuOqPqc5CW2kW) - A video series by Anthony Ferrara.
 * [Taking PHP Seriously](https://www.infoq.com/presentations/php-history) - A talk outlining PHP's strengths by Keith Adams of Facebook.
 
-## PHP Podcasts
+### PHP Podcasts
 *Podcasts with a focus on PHP topics.*
 
 * [PHP Town Hall](https://phptownhall.com/) - A casual PHP podcast by Ben Edmunds and Phil Sturgeon.
 * [PHP Roundtable](https://www.phproundtable.com/) - The PHP Roundtable is a casual gathering of developers discussing topics that PHP nerds care about.
 * [Voices of the ElePHPant](https://voicesoftheelephpant.com/) - Interviews with members of PHP community.
 
-## PHP Reading
+### PHP Reading
 *PHP-releated reading materials.*
 
 * [Composer Primer](https://daylerees.com/composer-primer/) - A Composer primer.
 * [Seven Ways to Screw Up BCrypt](https://blog.ircmaxell.com/2012/12/seven-ways-to-screw-up-bcrypt.html) - An article about correct BCrypt implementation.
 * [Use Env](https://seancoates.com/blogs/use-env/) - An article about using the unix environment helper.
 
-## PHP Internals Reading
+### PHP Internals Reading
 *Reading materials related to the PHP internals or performance.*
 
 * [Disproving the Single Quotes Myth](http://nikic.github.io/2012/01/09/Disproving-the-Single-Quotes-Performance-Myth.html) - An article about performance of single and double quoted strings.
 * Collecting Garbage: [1](http://php.net/manual/en/features.gc.refcounting-basics.php) [2](http://php.net/manual/en/features.gc.collecting-cycles.php) [3](http://php.net/manual/en/features.gc.performance-considerations.php) - A series about the PHP garbage collection internals.
 * PHP Source Code for Developers: [1](https://blog.ircmaxell.com/2012/03/phps-source-code-for-php-developers.html) [2](http://nikic.github.io/2012/03/16/Understanding-PHPs-internal-function-definitions.html) [3](https://blog.ircmaxell.com/2012/03/phps-source-code-for-php-developers_21.html) [4](http://nikic.github.io/2012/03/28/Understanding-PHPs-internal-array-implementation.html) - A series about the PHP source code.
 
-## PHP Magazines
+### PHP Magazines
 *Fantastic PHP-related magazines.*
 
 * [php[architect]](https://www.phparch.com/magazine/) - A monthly magazine dedicated to PHP.