使用设计：确认没有时间限制？

I'm using Devise for authentication in my application. I don't want to require email confirmation when a user signs up, but I do want to require it if the user wants the app to send them email updates. Is this possible with the built-in :confirmable feature of Devise? I found the setting to set how long a user can log in without confirming, but I essentially want to set that to "forever".I'm using Devise for authentication in my appli