Merge pull request #9 from halnique/feature/codeclimate

add cc badge

Author: halnique

README.md

@@ -4,6 +4,7 @@
 PHP string extensions.
 
 [![Build Status](https://travis-ci.com/halnique/php-string.svg?token=XvYo9WxYGLhpW4jmB1sm&branch=develop)](https://travis-ci.com/halnique/php-string)
+[![Maintainability](https://api.codeclimate.com/v1/badges/25648b3de2cc1249f7fc/maintainability)](https://codeclimate.com/github/halnique/php-string/maintainability)
 [![Latest Stable Version](https://poser.pugx.org/halnique/php-string/v/stable)](https://packagist.org/packages/halnique/php-string)
 [![Total Downloads](https://poser.pugx.org/halnique/php-string/downloads)](https://packagist.org/packages/halnique/php-string)
 [![Latest Unstable Version](https://poser.pugx.org/halnique/php-string/v/unstable)](https://packagist.org/packages/halnique/php-string)