Update README.md

Author: castarco

README.md

@@ -14,6 +14,8 @@ ColorSharp is available as a [nuget package](https://www.nuget.org/packages/Colo
  * [Project Documentation](https://github.com/Litipk/ColorSharp/wiki) : Here you can find how to use ColorSharp in your applications.
  * [External References](https://github.com/Litipk/ColorSharp/blob/master/REFERENCES.md) : Here you can learn about the science behind ColorSharp and discover other projects that have inspired us.
  * [Blog](https://colorsharp.wordpress.com/) : News, technical articles, opinion...
+ * [Chat Room](https://gitter.im/Litipk/ColorSharp) : If you want to have a real-time chat with other ColorSharp users or developers, you can do it here.
+ * [Group / Mail List](https://groups.io/org/groupsio/litipk_colorsharp) : If a chat room isn't enough to post your doubts or ideas, you can join to our mail list.
 
 ## Project Status