memo

class User
  .
  .
  #クラス変数へのアクセサ
  cattr_accessor(:current_user)
  .
  .
end

class ApplicationController
  .
  .
  def current_user
    return @current_user if @current_user

    @current_user = User.normal_select.find_by(remember_token: User.encrypt(cookies[:remember_token]), enable: true)
    User.current_user = @current_user
  end
  .
  .
end