Adding author to Projects and Documents

[Pivotal Tracker](https://www.pivotaltracker.com/story/show/63061078)
- Added `belongs_to` & `has_many` relationship for User => Document
- Added `belongs_to` & `has_many` relationship for User => Project
- Modified controllers for Documents & Projects to add `current_user.id` to params in `create`-method
- Created helper methods to display Author on show pages for Projects & Documents
- Added specs and cukes

#### +1 Fix for https://github.com/AgileVentures/WebsiteOne/issues/86 :-)

#### -1 Had to comment out `bootstrap.feature` due to failing results half of the time. We need to refactor those tests. :-(