Rails deviseによるユーザー認証 メールによる認証、emailとusernameのどちらでもログイン可能にするまで - Qiita=================================================================== Some setup you must do manually if you haven't yet: 1. Ensure you have defined default url options in your environments files. Here is an example of default_url_options appropriate for a development environment in config/environments/development.rb: config.action_mailer.default_url_options = { host: 'localhost', port: 3000 } In pr
