Add initial contribution guidelines

CONTRIBUTING.md

@@ -0,0 +1,18 @@
+# Contribution Guidelines
+
+When contributing to this repository, please first discuss the change you 
+wish to make via issue, email, or any other method with the owners of this 
+repository before making a change.
+
+## Pull Requests
+
+1. Fork this repository to your repository
+1. Clone the repository to your local machine
+1. Checkout the `dev` branch
+1. Make any changes to the code on the `dev` branch
+1. Push your changes to your fork
+1. Create new pull request
+
+## Documentation Strings
+
+Documentation strings are to follow the Google Style ([examples](https://sphinxcontrib-napoleon.readthedocs.io/en/latest/example_google.html)).