authenticable.rb

def update_with_password(params={})
  current_password = params.delete(:current_password)

  params.delete(:password)              if params[:password].blank?
  params.delete(:password_confirmation) if params[:password_confirmation].blank?

  skip_password_check = !(current_password.present? || params[:password] || params[:password_confirmation])
  
  result = if skip_password_check || valid_password?(current_password)
    update_attributes(params)
  else
    self.errors.add(:current_password, current_password.blank? ? :blank : :invalid)
    self.attributes = params
    false
  end

  clean_up_passwords unless result
  result
end