ActsAsList  provides the capabilities for sorting and reordering a number of objects in list. The class that has this specified needs to have a "position" column defined as an integer on the mapped database table[1]. 

Todo list example: 
<pre><code>
  class TodoList < ActiveRecord::Base
    has_many :todo_items, :order => "position"
  end

  class TodoItem < ActiveRecord::Base
    belongs_to :todo_list
    acts_as_list :scope => :todo_list
  end

  todo_list.first.move_to_bottom
  todo_list.last.move_higher
</code></pre>

h2. API documentation

* "ActiveRecord::Acts::List::ClassMethods":http://rails.rubyonrails.com/classes/ActiveRecord/Acts/List/ClassMethods.html
* "ActiveRecord::Acts::List::InstanceMethods":http://rails.rubyonrails.com/classes/ActiveRecord/Acts/List/InstanceMethods.html

h2. Examples

* Hierakis "Chapter":http://dev.hieraki.org/trac.cgi/file/trunk/app/models/chapter.rb and "Page":http://dev.hieraki.org/trac.cgi/file/trunk/app/models/page.rb models. See also the interesting implementation of "up/down/top/bottom" in the "chapter controller":http://dev.hieraki.org/trac.cgi/file/trunk/app/controllers/chapter_controller.rb
* "s5presents":http://www.s5presents.com/ Slide model(app\models\slide.rb) and controller(app\controllers\slide_controller.rb)


<hr />

fn1. Taken directly from the API