Listerine
==========

Listerine is a fast alternative to acts_as_list because the item that is being inserted or moved is the 
only one touched.  It does not reorder items below itself.  To do this you need to have a +position+ column 
defined as a float on the mapped database table.


Example
=======

  class TaskList < ActiveRecord::Base
    has_many :tasks, :order => "position"
  end

  class Task < ActiveRecord::Base
    belongs_to :task_list
    listerine :task_list, :tasks
  end

  first_task = task_list.tasks.create(:description => 'first task') # inserts item to the bottom of list by default
  first_task.move_to 3 # move to position 3
  first_task.move_to_top # move to top (same as move_to(1) )
  first_task.move_to_bottom # move to bottom

  any_task.cleanup_positions!
  
Notes
=====

The float gives us a resolution up to 1074 inserts in between two items.  We automatically re-index 
the entire list after 1000 inserts.  But, you can customize this by doing a cleanup_positions!
manually in a background or cron job so your user never experiences a full list re-order.


Credits
=======

Inspired by Dennis Collinson


Copyright (c) 2009 Rodney Carvalho, released under the MIT license