Create the ruby API app to manage sessions

[arthurmde]

• The APP only have to provide a JSON API without GUI.
• Consider to use Redis
• The API must provide methods to:
  • Request a new session ID: Returns the session code (preferably a small number that the user can easily copy by hand). OBS: still need to think how to manage session by stateless API
  • Post a new command with the session ID: the APP receives the Session Code and The Command. It must enqueue the command until receive a request for the next command.
  • Request the last command in the queue: the APP receives the Session Code and some identifier of the request object and returns the first command in the queue of that session.