Add better support for dev environment

- Add sinatra reloader, cause webrick wasn't reloading
  automatically(Don't ask me why);
- Add "pry", an incredible interactive debugger;
- Add "before filter" to check user credentials in most of pages.
Merge pull request #5 from romanoaugusto88/master

Add better support for dev environment
Add PostgreSQL and basic migrations

- Add PostgreSQL server;
- Scripts to setup PostgreSQL on Vagrant;
- Add active record migration;
- User migration;
- Register migration;
- Refactor the app config.
Merge pull request #6 from romanoaugusto88/postgre_and_base_migrations

Add PostgreSQL and basic migrations
Persists user on db

- And refactor the templates.
Merge pull request #7 from romanoaugusto88/persist_user

Persists user on db