Add Users model for storage admin user.
Add Sessions controller. Update routes for login-logout actions.
Updade specs for Session controller. Add factory for admin user.
Add specs for User model.
Add specs for named routes (Sessions controller).
Add simple authentication system.
Update specs and views for authenticate system.
Add fake authorisation system.
Refactoring: Add login_helper for specs, add fake_session routing spec, add specs for logout action.
Refactoring: update 'robots.txt' (block all robots), update sessions (sessions live = 30 minutes).