Change email without confirmation
@user = User.find_by_email('bob@site.com')
@user.email = 'dead@site.com'
@user.skip_reconfirmation!
@user.save!
Require password_confirmation when create new user
class User
validates :password_confirmation, presence: true, on: :create
end
Valid password
user.valid_password?(params[:user][:password])