class RailsSettingsMigration < ActiveRecord::Migration def self.up create_table :settings do |t| t.string :var, :null => false t.text :value t.references :target, :null => false, :polymorphic => true t.timestamps end add_index :settings, [ :target_type, :target_id, :var ], :unique => true end def self.down drop_table :settings end end