Added user activity feed by implementing a trackable polymorphic association.  Currently just comments & project creation count as activity but maybe in the future, downloads and views will be included (though I think it's weird when Linkedin does that).  Also made factories a bit less brittle while also implementing a project uploader helper.  Added a presenters class to help with the all the view logic and it might be nice to do that in other areas in the future.
Added styling for activity.  This activity feed is global and will be accessible to everyone.  The next logical step is to make these user specific.  I'd consider moving the activity into a partial when that work is done.
Merge pull request #13 from allcentury/user_activity

User activity