Adds contrib info.

CONTRIBUTING.md

@@ -0,0 +1,19 @@
+# Contributing to the Fn Java FDK
+
+We welcome all contributions!
+
+## How to contribute
+   * Fork the repo.
+   * Fix an issue. Or create an issue and fix it.
+   * Create a pull request. Reference the issue that you are fixing.
+   * Your branch will be built by our CI system. Make sure that this build passes.
+   * Be ready to respond to comments and questions from the community.
+   * Good job! Thanks for being awesome!
+
+## Tips for a swift merge
+   * Make sure your branch has no conflicts with master. Rebase often.
+   * Ensure that you have updated any JavaDoc or user/technical docs in `/docs`.
+   * Don't make breaking changes to the public APIs.
+   * Write tests - especially for public APIs.
+   * Make sure that changes to `api` are backwards compatible with `runtime` and vice-versa.
+

README.md

@@ -337,7 +337,11 @@ someone else to do their work.
 If this sounds like you, then have a look at the [Fn Flow
 quickstart](docs/FnFlowsUserGuide.md).
 
+# Get help
+
+   * Come over and chat to us on the [fnproject Slack](https://join.slack.com/t/fnproject/shared_invite/enQtMjIwNzc5MTE4ODg3LTdlYjE2YzU1MjAxODNhNGUzOGNhMmU2OTNhZmEwOTcxZDQxNGJiZmFiMzNiMTk0NjU2NTIxZGEyNjI0YmY4NTA).
+   * Raise an issue in [our github](https://github.com/fnproject/fn-java-fdk/).
 
 # Contributing
 
-*TBD*
+Please see [CONTRIBUTING.md](CONTRIBUTING.md).