Image url

Created a field in the database, associated forms and views, spec tests, and validator in lib/validators that allow a user to include an image with their project description by linking to a file hosted on a whitelisted website.

https://www.pivotaltracker.com/story/show/80235250
Also this is actually breaking Semaphore builds, Rails is very opinionated about filenames and the directory structure. The “v1” at the end is confusing Rails.