My app doesn't need the user to register. However I would like to get the email id of the users who use my app. On the android version of my app, users have to enter their email id before they can use the app. However Apple rejects apps which do that. What would be the best way to make users enter their email?

If I put the email registration screen along with a 'skip' button, will it be ok? Will Apple allow my app on the app store?