Add code analysis tool.

README.md

@@ -382,6 +382,7 @@ Please see [CONTRIBUTING](https://github.com/ziadoz/awesome-php/blob/master/CONT
 
 * [Better Reflection](https://github.com/Roave/BetterReflection) - AST-based reflection library that allows analysis and manipulation of code
 * [Code Climate](https://codeclimate.com) - An automated code review.
+* [GrumPHP](https://github.com/phpro/grumphp) - A PHP code-quality tool.
 * [PHP Parser](https://github.com/nikic/PHP-Parser) - A PHP parser written in PHP.
 * [PHP Semantic Versioning Checker](https://github.com/tomzx/php-semver-checker) - A command line utility that compares two source sets and determines the appropriate semantic versioning to apply.
 * [Phpactor](https://github.com/phpactor/phpactor) - PHP completion, refactoring and introspection tool.