Update README.md

Author: phillwiggins

README.md

@@ -3,6 +3,8 @@ A rewrite of a library hosted on GitHub. This is not my own content but based on
 
 https://github.com/lotux/parse_server_dart
 
+Want to get involved? Join our Slack channel and help out! flutterparsesdk.slack.com
+
 ## Getting Started
 
 ## To init Parse, call the method:-