docs(readme): add slack link to help section

README.md

@@ -56,9 +56,8 @@ Pact is most valuable for designing and testing integrations where you (or your
 
 * Pact docs: [docs.pact.io](http://docs.pact.io)
 * Ruby Pact wiki: [github.com/pact-foundation/pact-ruby/wiki](https://github.com/pact-foundation/pact-ruby/wiki)
+* Slack: <script async defer src="https://pact-slack.herokuapp.com/slackin.js?large"></script>
 * Stackoverflow: [ruby pact questions](https://stackoverflow.com/questions/tagged/pact-ruby) or [general pact questions](https://stackoverflow.com/questions/tagged/pact)
-* Google users group: [for ongoing discussions rather than questions](https://groups.google.com/forum/#!forum/pact-support)
-* Gitter: [![Join the chat at https://gitter.im/realestate-com-au/pact](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/realestate-com-au/pact?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 * Twitter: [@pact_up](https://twitter.com/pact_up)
 
 ## Installation