Merge pull request #567 from outsideris/badges-for-chat

add badges for Slack and Gitter

Author: keithamus

README.md

@@ -10,6 +10,8 @@
 
 [![Selenium Test Status](https://saucelabs.com/browser-matrix/chaijs.svg)](https://saucelabs.com/u/chaijs)
 
+[![Slack Status](https://chai-slack.herokuapp.com/badge.svg)]( https://chai-slack.herokuapp.com/)
+[![Join the chat at https://gitter.im/chaijs/chai](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/chaijs/chai)
 
 Chai is a BDD / TDD assertion library for [node](http://nodejs.org) and the browser that
 can be delightfully paired with any javascript testing framework.