grantcallendar/db/migrate/20220216133408_create_join_table.rb

class CreateJoinTable < ActiveRecord::Migration[5.2]
  def change
    create_join_table :users, :roles do |t|
      t.index [:user_id, :role_id]
      # t.index [:role_id, :user_id]
    end
  end
end