added how-to-contribute (#736)

docs/README.md

@@ -1,4 +1,26 @@
+[![Documentation Status](https://readthedocs.org/projects/goquorum/badge/?version=latest)](http://docs.goquorum.com/en/latest/?badge=latest)
 
 # Quorum documentation
 
-New Quorum documentation is now published on https://goquorum.readthedocs.io/
+New Quorum documentation is now published on https://docs.goquorum.com/
+
+## How to contribute
+
+Quorum documentation files are written in Markdown and configured with a
+YAML configuration file from [mkdocs](https://www.mkdocs.org/)
+
+The documentation site uses [Material theme](https://squidfunk.github.io/mkdocs-material/)
+which has been configured with number of theme [extensions](https://squidfunk.github.io/mkdocs-material/extensions/admonition/)
+to enhance documenting experience 
+
+To contribute, here is 3 simple steps
+
+- Use Python to install `mkdocs` and related dependencies
+    ```bash
+    pip install -r requirements.txt
+    ```
+- Add/Modify desired documentation files and preview the site
+    ```bash
+    mkdocs serve
+    ```
+- Commit and raise PR against master