Massive refactor of backend to use ActiveRecord and Modular Sinatra

Refactor the Sinatra backend to use a modular style to help separate the
backend and frontend parts of the application. ActiveRecord was used in
place of DataMapper so as to increase the options of using
authentication gems.
Clean up repository and update Travis script

Travis CI was complaining about the lack of table. Add a script to run
rake db:migrate to hopefully fix this.
Update .travis.yml

Prefixed script with 'bundle exec'.
Update .travis.yml

Reformat for readability.