cheat sheets.

See: http://technoweenie.stikipad.com/plugins/show/User+Authentication

Install:
>> ruby script/plugin source http://svn.techno-weenie.net/projects/plugins
>> ruby script/plugin install acts_as_authenticated

Generate:
>> ruby script/generate authenticated user account
>> rake db:migrate

To require logins for all actions, use this in your controllers:
  before_filter :login_required

To require logins for specific actions, use this in your controllers:
  before_filter :login_required, :only => [ :edit, :update ]

To skip this in a subclassed controller:
  skip_before_filter :login_required

Here are other available methods for your views and controllers:
    * logged_in? – Returns true if the user is currently logged in.
    * current_user – Returns an instance of the currently logged in user.

You can override the #protect? method in your controller to only protect certain
actions:

  # don't protect the login and the about method
  def protect?(action)
    if ['login', 'about'].include?(action)
       return false
    else
       return true
    end
  end

You can also override #authorized? in your controller to restrict the actions
based on the user:

  # only allow nonbobs
  def authorized?(user)
    user.login != "bob" 
  end