[docs] Update Contributing Section in docs.

* Add testing details
* Add linting step
* Add CONTRIBUTING.md

CONTRIBUTING.md

@@ -0,0 +1 @@
+Please read the [Contribution Guidelines in Mozillians.org Documentation](http://mozillians.readthedocs.org/en/latest/contribute.html).

docs/contribute.rst

@@ -29,10 +29,24 @@ When you want to start contributing, you should :doc:`follow the installation in
 
 #. Commit changes to the code!
 
+#. Code!
+
+#. Lint the code::
+
+    $ flake8 mozillians
+
+   and fix any errors.
+
 #. Run the tests::
 
     $ ./manage.py test
 
+   and make sure that all tests pass.
+
+   Learn more about :doc:`testing </testing>`.
+
+#. Commit changes to the code!
+
 #. When you're done, figure out how many commits you've made::
 
     $ git log

docs/testing.rst

@@ -2,6 +2,28 @@
  Testing
 =========
 
+Testing Mozillians Code
+-----------------------
+
+* To run mozillians.org tests::
+
+  $ ./manage.py test
+
+* If you need a fresh test database::
+
+  $ FORCE_DB=1 ./manage.py test
+
+* To run all tests in a class::
+
+  $ ./manage.py test mozillians.users.tests.test_models:UserProfileTests
+
+* If you want to run a single test::
+
+  $ ./manage.py test mozillians.users.tests.test_models:UserProfileTests.test_get_attribute_with_public_level
+
+  to run only `test_get_attribute_with_public_level` test from the `UserProfileTests` class in the `mozillians/users/tests/test_models.py` test file.
+
+
 Test Coverage
 -------------