I'm running Rails 2.0 and I'm getting this error (undefined method `acts_as_tree') when trying to use the 'acts_as_tree' functionality in one of my models:
class Topic < ActiveRecord::Base has_many :pages has_many :screens, :through => :pages has_many :folders has_many :courses, :through => :folders acts_as_tree :order => "title" end
I have the "topic" table in my db setup as follows:
create_table :topics do |t| t.string :title t.integer :parent_id end
What gives?