class CreateSettings < ActiveRecord::Migration[4.2] def self.up create_table :settings do |t| t.string :var, null: false t.text :value, null: true t.integer :thing_id, null: true t.string :thing_type, limit: 30, null: true t.timestamps end add_index :settings, [ :thing_type, :thing_id, :var ], unique: true end def self.down drop_table :settings end end