photomix/db/migrate/20090604202930_create_roles.rb

class CreateRoles < ActiveRecord::Migration
  def change
    create_table :roles do |t|
      t.string :name

      t.timestamps
    end

    create_table :roles_users, :id => false, :force => true do |t|
      t.references :role
      t.references :user
    end

    add_index :roles_users, :role_id, :name => 'index_roles_users_on_role_id'
    add_index :roles_users, :user_id, :name => 'index_roles_users_on_user_id'
  end

end