[#55467310] Add the rails_12factor gem.

- As recommended in https://devcenter.heroku.com/articles/rails4
[#55467310] Start tracking bin/

- Needed by Heroku for rails 4 – https://devcenter.heroku.com/articles/rails4
- Also lock the ruby version in the Gemfile.
Validate uniqueness of email address across the whole app.
Add the GPL v3 License
Remove stray files in the root of the repo