Added information on contribution & bug reporting

Readme.md

@@ -23,3 +23,13 @@ fit.
 
 When ready, use `cd` into `production` and use `docker compose up` to run the
 resulting production ready image.
+
+## Contributing & bug reports
+
+To contribute:
+
+ - commit all changes to a publicly accessible git repository.
+
+ - add the output of `git request-pull` and a description of your changes to
+   `cc-writefreely@googlegroups.com` via email or through the
+   [web ui](https://groups.google.com/g/cc-writefreely).