Merge pull request angular-ui#3198 from gitter-badger/gitter-badge-1

Add a Gitter chat badge to README.md

Author: karianna

README.md

@@ -1,5 +1,7 @@
 # bootstrap - [AngularJS](http://angularjs.org/) directives specific to [Bootstrap](http://getbootstrap.com)
 
+[![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/angular-ui/bootstrap?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+
 ***
 
 [![Build Status](https://secure.travis-ci.org/angular-ui/bootstrap.svg)](http://travis-ci.org/angular-ui/bootstrap)