docs: Convert slack links to CNCF, add link to contributing guide (#1047)

Co-authored-by: Assem Hafez <[email protected]>
Co-authored-by: Adhitya Mamallan <[email protected]>

Author: 3 people

CONTRIBUTING.md

@@ -2,6 +2,12 @@
 
 This doc is intended for contributors to `cadence-web`
 
+> 📚 **New to contributing to Cadence?** Check out our [Contributing Guide](https://cadenceworkflow.io/community/how-to-contribute/getting-started) for an overview of the contribution process across all Cadence repositories. This document contains cadence-web specific setup and development instructions.
+
+Once you go through the rest of this doc and get familiar with local development setup, feel free to start contributing!
+
+Join our community on the CNCF Slack workspace at [cloud-native.slack.com](https://communityinviter.com/apps/cloud-native/cncf) in the **#cadence-users** channel to reach out and discuss issues with the team.
+
 **Note:** All contributors will be asked to sign [Uber Contributor License Agreement](http://t.uber.com/cla) during the PR process.
 
 ## Development Environment

README.md

@@ -1,6 +1,7 @@
 # Cadence Web UI
 
 [![Build Status](https://github.com/uber/cadence-web/actions/workflows/build.yml/badge.svg)](https://github.com/uber/cadence-web/actions/workflows/build.yml) [![Docker Status](https://github.com/uber/cadence-web/actions/workflows/docker_publish.yml/badge.svg)](https://hub.docker.com/r/ubercadence/web/tags)
+[![Slack Status](https://img.shields.io/badge/slack-join_chat-white.svg?logo=slack&style=social)](https://communityinviter.com/apps/cloud-native/cncf)
 
 Cadence is a distributed, scalable, durable, and highly available orchestration engine we developed at Uber Engineering to execute asynchronous long-running business logic in a scalable and resilient way.
 
@@ -165,6 +166,12 @@ After running `cadence`, start `cadence-web` for development using one of the pr
 | lint              | Run eslint                                                                                      |
 | typecheck         | Run typescript checks                                                                           |
 
+## Contributing
+
+We'd love your help in making the Cadence Web UI great. Please review our [contribution guidelines](CONTRIBUTING.md).
+
+If you'd like to propose a new feature or discuss issues, join the [CNCF Slack workspace](https://communityinviter.com/apps/cloud-native/cncf) in the **#cadence-users** channel to start a discussion.
+
 ## License
 
 Apache 2.0 License, please see [LICENSE](https://github.com/cadence-workflow/cadence-web/blob/master/LICENSE) for details.