Add Discourse to readme and make it more prominent in docs. (#12740)

README.rst

@@ -6,6 +6,9 @@
 .. image:: https://img.shields.io/badge/Ray-Join%20Slack-blue
     :target: https://forms.gle/9TSdDYUgxYs8SA9e8
 
+.. image:: https://img.shields.io/badge/Discuss-Ask%20Questions-blue
+    :target: https://discuss.ray.io/
+
 |
 
 

doc/source/getting-involved.rst

@@ -6,7 +6,10 @@ Getting Involved / Contributing
 Ray is more than a framework for distributed applications but also an active community of developers,
 researchers, and folks that love machine learning.
 
-.. tip:: Join our `community slack <https://forms.gle/9TSdDYUgxYs8SA9e8>`_ to discuss Ray! The community is extremely active in helping people succeed in building their ray applications.
+.. tip:: Join our `community Slack <https://forms.gle/9TSdDYUgxYs8SA9e8>`_ to
+  discuss Ray or ask questions on `our forum <https://discuss.ray.io/>`_! The
+  community is extremely active in helping people succeed in building their
+  Ray applications.
 
 You can join (and Star!) us on `on GitHub`_.
 

doc/source/ray-overview/involvement.rst

@@ -1,7 +1,7 @@
 Ray is more than a framework for distributed applications but also an active community of developers,
 researchers, and folks that love machine learning. Here's a list of tips for getting involved with the Ray community:
 
-- Join our `community slack <https://forms.gle/9TSdDYUgxYs8SA9e8>`_ to discuss Ray!
+- Join our `community Slack <https://forms.gle/9TSdDYUgxYs8SA9e8>`_ to discuss Ray!
 - Star and follow us on `on GitHub`_.
 - To post questions or feature requests, check out the `Discussion Board`_!
 - Follow us and spread the word on `Twitter`_!