Notification: Inform admin when ad submitted for review

[wtogami]

Note: This could be problematic if the user can submit ads for review without any limit as it would send an e-mail per submission. This can be safeguarded with a payment required on every submission for review or a submission rate limit enforced by the app.

[taesup]

Right now there's a section in the admin page where all submitted ads can be viewed and reviewed from. I think this may be a better option as the admin can just keep checking this page without having to worry about mass emails.

Maybe a daily email could be sent out instead that recaps the number of ads submitted? or an hourly email with the latest number of submitted ads, or no email if there are none.

As for rate limiting the number of submitted ads, I think there does need to be some sort of limiting system but I'm not sure about the payment route. Maybe a limit on the number of ads a user can have that can be lifted by an admin?