gistfile1.txt

Migration:

class CreateJoinTableCommandTag < ActiveRecord::Migration
  def change
    create_join_table :commands, :tags do |t|
      # t.index [:command_id, :tag_id]
      # t.index [:tag_id, :command_id]
    end
  end
end

Model:

class CommandTag < ActiveRecord::Base
  belongs_to :command
  belongs_to :tag
end