Update README.md

Author: gkorland

README.md

@@ -9,7 +9,7 @@
 
 # JRedisJSON
 
-[![Mailing List](https://img.shields.io/badge/Mailing%20List-RedisJSON-blue)](https://groups.google.com/forum/#!forum/redisjson)
+[![Forum](https://img.shields.io/badge/Forum-RedisJSON-blue)](https://forum.redislabs.com/c/modules/redisjson)
 [![Gitter](https://badges.gitter.im/RedisLabs/RedisJSON.svg)](https://gitter.im/RedisLabs/RedisJSON?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)