Description:
    Generates a user model, users controller, and sessions controller. The
    users controller handles the registration and the sessions controller
    handles authentication. This is similar to restful_authentication, but
    simpler.

    IMPORTANT: This generator uses the "title" helper method which is generated
    by the haml_layout generator. You may want to run that generator first.

Usage:
    If you do not pass any arguments, the model name will default to "user", and
    the authentication controller will default to "session". You can override
    each of these respectively by passing one or two arguments. Either name can
    be CamelCased or under_scored.

Examples:
    rails generate zoo:authentication

        Creates user model, users_controller, and sessions_controller.

    rails generate zoo:authentication account

        Creates account model, accounts_controller, and sessions_controller.

    rails generate zoo:authentication Account UserSession

        Creates account model, accounts_controller, and user_sessions_controller.

Methods:
    There are several methods generated which you can use in your application.
    Here's a common example of what you might add to your layout.

      <% if logged_in? %>
        Welcome <%= current_user.username %>! Not you?
        <%= link_to "Log out", logout_path %>
      <% else %>
        <%= link_to "Sign up", signup_path %> or
        <%= link_to "log in", login_path %>.
      <% end %>

    You can also restrict unregistered users from accessing a controller using
    a before filter. For example.

      before_filter :login_required, except: [:index, :show]

    See the generated file lib/authentication.rb for details.