Add Gitter badge

README.md

@@ -1,5 +1,7 @@
 ## netboot.xyz
 
+[![Join the chat at https://gitter.im/antonym/netboot.xyz](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/antonym/netboot.xyz?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+
 [![Build Status](https://travis-ci.org/antonym/netboot.xyz.svg?branch=master)](https://travis-ci.org/antonym/netboot.xyz) [![Doc Status](https://readthedocs.org/projects/netbootxyz/badge/?version=latest)](https://readthedocs.org/projects/netbootxyz)
 
 ### What is netboot.xyz?