class LinkGuidanceToGuidanceGroups < ActiveRecord::Migration def self.up create_table :guidance_in_group, :id => false do |t| t.references :guidance, :null => false t.references :guidance_group, :null => false end add_index :guidance_in_group, [:guidance_id, :guidance_group_id] end def self.down drop_table :guidance_in_group end end