Point chat badge to IRC instead

No longer using Gitter (too hard to manage multiple communication channels)

README.md

@@ -3,7 +3,7 @@
 [![Homepage](http://img.shields.io/badge/home-yardoc.org-blue.svg)](http://yardoc.org)
 [![GitHub](http://img.shields.io/badge/github-lsegal/yard-blue.svg)](http://github.com/lsegal/yard)
 [![Documentation](http://img.shields.io/badge/docs-rdoc.info-blue.svg)](http://rubydoc.org/gems/yard/frames)
-[![Gitter Chat](http://img.shields.io/badge/chat-gitter.im-orange.svg)](https://gitter.im/lsegal/yard)
+[![IRC Chat](https://img.shields.io/badge/chat-%23yard%20@%20freenode-orange.svg)](irc://irc.freenode.net/yard)
 
 [![Gem Version](https://badge.fury.io/rb/yard.svg)](http://github.com/lsegal/yard/releases)
 [![Build Status](https://travis-ci.org/lsegal/yard.svg?branch=master)](https://travis-ci.org/lsegal/yard)