Add Bolt to new CMS category.

README.md

 	- [Frameworks](#frameworks)
 	- [Framework Components](#framework-components)
 	- [Micro Frameworks](#micro-frameworks)
+	- [Content Management Systems](#content-management-systems)
 	- [Templating](#templating)
 	- [HTTP](#http)
 	- [URL](#url)
 * [Bullet PHP](http://bulletphp.com/) - A mico framework for building REST APIs.
 * [Klein](https://github.com/chriso/klein.php) - A fast routing library.
 
+## Content Management Systems
+*Modern content management systems.*
+
+* [Bolt](https://github.com/bolt/bolt) - A simple CMS built with Silex and Twig.
+
 ## Templating
 *Libraries and tools for templating and lexing.*