Tests post twitter helper addition

Please please *PLEASE* do not merge this to master. This is just a pull request so it can be viewed properly. There are commented out tests because the Twitter helper broke nearly all of the tests, and lowered the test coverage. I've gotten OmniAuth to go into test mode for testing, but it sends an invalid authorization error if anything goes through the helper method (obviously, because the token *is* invalid). That means that post creation cannot be tested *at all* until this is fixed. 

Some ideas to get around it:

* Create a test Twitter account in order to have valid oauth tokens and secrets

* Research stubbing requests to Twitter (will take time, but this is probably the proper way to do it)

* Ask a teacher/phase 4 person for help