Scope for each state in the pluginaweek/state_machine

thing.rb

class Thing < ActiveRecord::Base
  state_machine :initial => :pending do
    # when published, the thing has to be removed
    after_transition :on => :done_publishing, :do => :destroy

    event :publish do
      transition :pending => :publishing, :unless => :not_ready?
    end

    event :done_publishing do
      transition :publishing => :published
    end

    state :pending, :publishing, :published
  end

  # now, one scope for each state so we can do Thing.pending, Thing.publishing and Thing.published
  #
  state_machine.states.collect(&:name).each do |name|
    scope name, where(:state => name)
  end
end