Add CONTRIBUTING doc.

Author: carljm

CONTRIBUTING.rst

@@ -0,0 +1,59 @@
+Contributing
+============
+
+Contributions of code and documentation are always welcome!
+
+
+Submitting Issues
+-----------------
+
+Issues are easier to reproduce and resolve when they include:
+
+- A pull request with a failing test demonstrating the issue (no need to file
+  both a pull request and an issue, the pull request is sufficient).
+- A code example that produces the issue consistently
+- A traceback (when applicable)
+
+
+Pull Requests
+-------------
+
+When creating a pull request, try to:
+
+- Write tests that fail before your change and pass after it
+- Note important changes in the `CHANGES`_ file
+- Update the `README`_ file as needed
+- Add yourself to the `AUTHORS`_ file
+
+.. _AUTHORS: AUTHORS.rst
+.. _CHANGES: CHANGES.rst
+.. _README: README.rst
+
+
+Testing
+-------
+
+Please add tests for your code and ensure existing tests don't break.  To run
+the tests against your code::
+
+    python setup.py test
+
+You can use `tox`_ to test the code against supported Python and Django
+versions.  First install tox::
+
+    pip install tox
+
+To run tests using tox::
+
+    tox
+
+To fully run the tests via tox, you must have python2.6, python2.7, and
+python3.3 interpreters on your system, available by those names. If you are
+missing one or more interpreters, tox will skip testing against that Python
+version and notify you.
+
+When submitting a pull request, please note whether you've run the tests with
+tox (and against which versions). Before a pull request can be merged, all
+tests must pass on all configured tox environments.
+
+.. _tox: http://tox.readthedocs.org/en/latest/