Hello everyone. Hope you can help me with a small question.

I am making a website where different students from my school can create their own profiles/portolios. In order to do that I want them to register and create their page, but I want to make sure that its only students from my school who can register.

I was thinking of adding "Answer following question:" field to the registration page, so I don't have to manually approve users.

Question is: How can I add this kind of field in the registration form?