Added MIT license badge to the README.

Author: jdantonio

README.md

@@ -1,5 +1,5 @@
 # Concurrent Ruby
-[![Gem Version](https://badge.fury.io/rb/concurrent-ruby.png)](http://badge.fury.io/rb/concurrent-ruby) [![Build Status](https://travis-ci.org/ruby-concurrency/concurrent-ruby.svg?branch=master)](https://travis-ci.org/ruby-concurrency/concurrent-ruby) [![Coverage Status](https://coveralls.io/repos/ruby-concurrency/concurrent-ruby/badge.png)](https://coveralls.io/r/ruby-concurrency/concurrent-ruby) [![Code Climate](https://codeclimate.com/github/ruby-concurrency/concurrent-ruby.png)](https://codeclimate.com/github/ruby-concurrency/concurrent-ruby) [![Inline docs](http://inch-ci.org/github/ruby-concurrency/concurrent-ruby.png)](http://inch-ci.org/github/ruby-concurrency/concurrent-ruby) [![Dependency Status](https://gemnasium.com/ruby-concurrency/concurrent-ruby.png)](https://gemnasium.com/ruby-concurrency/concurrent-ruby) [![Gitter chat](https://badges.gitter.im/ruby-concurrency/concurrent-ruby.png)](https://gitter.im/ruby-concurrency/concurrent-ruby)
+[![Gem Version](https://badge.fury.io/rb/concurrent-ruby.png)](http://badge.fury.io/rb/concurrent-ruby) [![Build Status](https://travis-ci.org/ruby-concurrency/concurrent-ruby.svg?branch=master)](https://travis-ci.org/ruby-concurrency/concurrent-ruby) [![Coverage Status](https://coveralls.io/repos/ruby-concurrency/concurrent-ruby/badge.png)](https://coveralls.io/r/ruby-concurrency/concurrent-ruby) [![Code Climate](https://codeclimate.com/github/ruby-concurrency/concurrent-ruby.png)](https://codeclimate.com/github/ruby-concurrency/concurrent-ruby) [![Inline docs](http://inch-ci.org/github/ruby-concurrency/concurrent-ruby.png)](http://inch-ci.org/github/ruby-concurrency/concurrent-ruby) [![Dependency Status](https://gemnasium.com/ruby-concurrency/concurrent-ruby.png)](https://gemnasium.com/ruby-concurrency/concurrent-ruby) [![License](http://img.shields.io/license/MIT.png?color=green)](http://opensource.org/licenses/MIT) [![Gitter chat](https://badges.gitter.im/ruby-concurrency/concurrent-ruby.png)](https://gitter.im/ruby-concurrency/concurrent-ruby)
 
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