removed outdated Slack badge, added discussion link (#1327)

README.md

@@ -1,6 +1,6 @@
 <img src="https://avatars2.githubusercontent.com/u/2810941?v=3&s=96" alt="Google Cloud Platform logo" title="Google Cloud Platform" align="right" height="96" width="96"/>
 
-# Google Cloud Platform Community [![Slack][slack_badge]][slack_link] [![Build][build_badge]][build_link]
+# Google Cloud Community [![Build][build_badge]][build_link]
 
 This repository holds the content submitted to
 [cloud.google.com/community][community].
@@ -16,6 +16,7 @@ Find out how you can contribute at
 * [Browse tutorials][tutorials]
 * [Request a tutorial][request]
 * [Submit a tutorial][write]
+* [Ask a question or discuss Google Cloud][discuss]
 
 ## License
 
@@ -27,8 +28,7 @@ code samples are licensed under the [Apache 2.0 License][apache]._
 
 See [LICENSE](LICENSE.md).
 
-[slack_badge]: https://img.shields.io/badge/slack-gcp-E01563.svg?style=flat
-[slack_link]: https://gcp-slack.appspot.com/
+[discuss]: https://cloud.google.com/community/#home-support
 [build_badge]: https://img.shields.io/circleci/project/github/GoogleCloudPlatform/community/master.svg?style=flat
 [build_link]: https://circleci.com/gh/GoogleCloudPlatform/community
 [folder]: https://github.com/GoogleCloudPlatform/community/tree/master/tutorials