Wrote Feature model and add_favorite feature spec

  add config in rails_helper for FactoryGirl usage
  add user Factory
Fixed database issue on previous commit

  Added a signed in user to the create_bookmark feature spec

  Potential Issues:
  If there is no logged in user, favorited method could be called on Nil
    class.
Merge pull request #13 from runyans7/like-bookmarks

Like bookmarks