Update README.md

Author: rogerclarkmelbourne

README.md

@@ -14,6 +14,7 @@ This repo contains, the "Hardware" files to support STM32 based boards on Arduin
 ***PRIMARY SUPPORT FORUM: http://www.stm32duino.com/***
 
 ***We are also on Gitter https://gitter.im/stm32duino/Lobby/***
+[![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/stm32duino/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 
 ##Background & Support:  
 * Based on https://github.com/bobc/maple-asp, which is in turn based on LibMaple by Leaflabs