Change Gemfile
* modified application_controller [current_user, authorize]
* modified Gemfile
* added roles_controller [CRUD]
* added sessions_controller to handle application login
* added users_controller[CRUD]
* modified application_helper [get_user_name]
* created various default helpers
* created  user model, role model and added validation methods
* created application and sessions layouts
* modified routes.rb
* added users, sessions, roles views
* created and modifies users and role migrations
* added a formatter for Log messages
* removed original welcome page