ログインに利用するキーを変更するには通常 config/initializers/devise.rbの中の # ==> Configuration for any authentication mechanism # Configure which keys are used when authenticating a user. The default is # just :email. You can configure i…

saved_changeや(項目名)_previous_changeを使って変更を確認する user = User.new user.email = "test@example.com" user.save p user.email_previous_change ["", "test@example.com"] class User < ApplicationRecord after_save :do_somothing_if_email_c…