Update contribution doc to show users how to reach out via slack (#936)

* Update contribution doc to show users how to reach out via slack and discussion forum

* Add to readme as well

CONTRIBUTING.md

@@ -8,6 +8,13 @@ This guide details how to use issues and pull requests to improve KubeRay projec
 
 ## General Guidelines
 
+### Getting involved
+Kuberay has an active community of developers. Here’s how to get involved with the Kuberay community:
+
+Join our community: Join [Ray community slack](https://forms.gle/9TSdDYUgxYs8SA9e8) (search for Kuberay channel) or use our [discussion board](https://discuss.ray.io/c/ray-clusters/ray-kubernetes) to ask questions and get answers.
+
+Please see Github Issue section below to file bug & feature requests.
+
 ### Pull Requests
 
 Make sure to keep Pull Requests small and functional to make them easier to review, understand, and look up in commit history. This repository uses "Squash and Commit" to keep our history clean and make it easier to revert changes based on PR.

README.md

@@ -83,6 +83,11 @@ kubectl get pods
 
 Please read our [CONTRIBUTING](CONTRIBUTING.md) guide before making a pull request. Refer to our [DEVELOPMENT](./ray-operator/DEVELOPMENT.md) to build and run tests locally.
 
+### Getting involved
+Kuberay has an active community of developers. Here’s how to get involved with the Kuberay community:
+
+Join our community: Join [Ray community slack](https://forms.gle/9TSdDYUgxYs8SA9e8) (search for Kuberay channel) or use our [discussion board](https://discuss.ray.io/c/ray-clusters/ray-kubernetes) to ask questions and get answers.
+
 ## Security
 
 If you discover a potential security issue in this project, or think you may