Add RunKeeper

This is just a conversation starter at this point. This is working locally, but I'm having a terrible time getting tests to run. I've followed [the directions](https://github.com/omab/python-social-auth/tree/master/social/tests) with no luck and am getting lots of errors like the one below.

    AssertionError: <bound method EvernoteOAuth1ErrorTest.do_login of <social.apps.django_app.tests.EvernoteOAuth1ErrorTest testMethod=test_login>> should raise <class 'requests.exceptions.HTTPError'>, but raised <type 'exceptions.ValueError'>