http://youichi-kato.cocolog-nifty.com/blog/2008/01/rails_202_5_9198.html
ʂ̃TCgɃWv悤ƂĂ܂BXΏL̃NNbNĂ
UPLIFTōLȂő̌܂傤IKȉ{Ct܂I