Add Gitter badge

README.md

@@ -4,6 +4,8 @@
 
 # Wiki.js
 
+[![Join the chat at https://gitter.im/Requarks/wiki](https://badges.gitter.im/Requarks/wiki.svg)](https://gitter.im/Requarks/wiki?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+
 [![Release](https://img.shields.io/github/release/Requarks/wiki.svg?style=flat-square&maxAge=3600)](https://github.com/Requarks/wiki/releases)
 [![License](https://img.shields.io/badge/license-AGPLv3-blue.svg?style=flat-square)](https://github.com/requarks/wiki/blob/master/LICENSE)
 [![npm](https://img.shields.io/badge/npm-wiki.js-blue.svg?style=flat-square)](https://www.npmjs.com/package/wiki.js)