ActsAsPositioned is a featherweight gem for keeping records organized by position. We wrote it because keeping slideshow slides organized in RailsAdmin and Typus was frustrating. Stuff should just go where you put it.

ActsAsPositioned borrows much from ActsAsList, but does less and is more useful in today's Rails 3 universe.

1. You are using Rails 3.1 or higher.

Add this to your gemfile:

gem 'acts_as_positioned', :git => 'git://github.com/stager94/acts_as_positioned.git'

Run bundle install.

Run rails generate position MODEL

The generator creates a migration to add a position column of type integer to the specified model.

Run rake db:migrate

Call acts_as_positioned in your models.

class Slide < ActiveRecord::Base
  # this is the good bit:
  acts_as_positioned 

  # remember to order by position, either here or in your controllers.
  default_scope order(:position)
end

If positions aren't unique -- suppose you're organizing 24 songs under 2 albums -- supply an :under option.

class Song < ActiveRecord::Base
  belongs_to :album  
  acts_as_positioned :under => :album
end

Write to [email protected].