Install Sinatra gem

A Gemfile has been created, and the Sinatra gem has been added. Also, the Ruby version has been fixed since our development machine supports only Ruby version 2.0.
Create application

The application's logic is contained in the file app.rb.
Install and configure ActiveRecord

This application uses ActiveRecord as the ORM. Although this may introduce a small overhead, AR's features totally make up for it.
Install and configure Unicorn

Unicorn is an application server that can handle multiple requests in parallel by using threads.
Install JSON helper

The Sinatra::Contrib project provides a JSON helper that allows to easily return JSON encoded objects.
Merge branch 'feature/create-application' into develop