Add Code Climate badge

README.md

-# Welcome to GitLab [![build status](https://secure.travis-ci.org/gitlabhq/gitlabhq.png)](https://secure.travis-ci.org/gitlabhq/gitlabhq) [![build status](https://secure.travis-ci.org/gitlabhq/grit.png)](https://secure.travis-ci.org/gitlabhq/grit)
+# Welcome to GitLab [![build status](https://secure.travis-ci.org/gitlabhq/gitlabhq.png)](https://secure.travis-ci.org/gitlabhq/gitlabhq) [![build status](https://secure.travis-ci.org/gitlabhq/grit.png)](https://secure.travis-ci.org/gitlabhq/grit) [![Code Climate](https://codeclimate.com/badge.png)](https://codeclimate.com/github/gitlabhq/gitlabhq)
 GitLab is a free project and repository management application