Split README.rst into appropriate docs sections

docs/contributing.rst

@@ -0,0 +1,25 @@
+Contributing
+============
+
+Running VCR's test suite
+------------------------
+
+The tests are all run automatically on `Travis
+CI <https://travis-ci.org/kevin1024/vcrpy>`__, but you can also run them
+yourself using `py.test <http://pytest.org/>`__ and
+`Tox <http://tox.testrun.org/>`__. Tox will automatically run them in
+all environments VCR.py supports. The test suite is pretty big and slow,
+but you can tell tox to only run specific tests like this::
+
+    tox -e py27requests -- -v -k "'test_status_code or test_gzip'"
+
+This will run only tests that look like ``test_status_code`` or
+``test_gzip`` in the test suite, and only in the python 2.7 environment
+that has ``requests`` installed.
+
+Also, in order for the boto tests to run, you will need an AWS key.
+Refer to the `boto
+documentation <http://boto.readthedocs.org/en/latest/getting_started.html>`__
+for how to set this up. I have marked the boto tests as optional in
+Travis so you don't have to worry about them failing if you submit a
+pull request.