Add docs badge to README

Author: rrrene

README.md

@@ -5,12 +5,14 @@
 [![Dependency Status](https://img.shields.io/gemnasium/sferik/rails_admin.svg)][gemnasium]
 [![Code Climate](https://img.shields.io/codeclimate/github/sferik/rails_admin.svg)][codeclimate]
 [![Coverage Status](https://img.shields.io/coveralls/sferik/rails_admin.svg)][coveralls]
+[![Inline docs](http://inch-ci.org/github/sferik/rails_admin.svg)][inch]
 
 [gem]: https://rubygems.org/gems/rails_admin
 [travis]: http://travis-ci.org/sferik/rails_admin
 [gemnasium]: https://gemnasium.com/sferik/rails_admin
 [codeclimate]: https://codeclimate.com/github/sferik/rails_admin
 [coveralls]: https://coveralls.io/r/sferik/rails_admin
+[inch]: http://inch-ci.org/github/sferik/rails_admin
 
 RailsAdmin is a Rails engine that provides an easy-to-use interface for managing your data.