Doorkeeperでログイン中にエラーが発生すると、Doorkeeper::TokensControllerの中でエラーが起きるので、ApplicationController
/config/routes.rb
MyAppServer::Application.routes.draw do
use_doorkeeper do
controllers tokens: 'tokens'
end
resources :books
resources :users
end
/app/controllers/tokens_controller.rb
class TokensController
