page.rb

class Page < ActiveRecord::Base
  acts_as_tree
  
  def self.tree
    hash = find(:all).inject({}) { |hash, p| hash[p.id] = [p, []]; hash }
    hash.inject([]) { |result, (key, value)|
      if parent_id = value.first.parent_id
        hash[parent_id].last << value
      else
        result << value
      end
      
      result
    }
  end
end