add devise; rails g devise:install; rails g devise User;
prevent users from registering and canceling;
custom sign in/out views;
rails g migration add_username_and_role_to_users username:string role:integer
add login;
change role format from integer to string; add priviledges;
adding users spec;
move public methods to helpers; add spec;
rails g scaffold_controller Users role:string username:string email:string password:string