class AddTopicAllowedGroups < ActiveRecord::Migration[4.2] def change create_table :topic_allowed_groups, force: true do |t| # oops t.integer :group_id, :integer, null: false t.integer :topic_id, :integer, null: false end add_index :topic_allowed_groups, [:group_id, :topic_id], unique: true add_index :topic_allowed_groups, [:topic_id, :group_id], unique: true end end