reorganize Gemfile to prepare deployment
Configure Procfile for Heroku
Add guard-rails.

- To start guard and the rails server in development use "guard start" instead of "foreman start" from now on
- "foreman start" will use the Procfile configured for Heroku and no longer starts guard.
Move asset gems to asset group.

- Move backbone-on-rails to assets group to make it available for asset precompilation.
- Move sass-rails to assets group. It's not required in production.
Delete unused cucumber task.
Separate production seed from test data.

- to load production data use rake db:seed
- to load the test setup use rake db:load_test_data
Precompile map.js.