Ok, I have a website with a small number of roles, only 3 or so. I understand how to set those up. I also understand how to define which roles have access to which areas. What I don't understand is how to give people their roles. For instance, when a user signs up, if they select a certain user type, then they get a corresponding role that gives them access to a portion of the website.

Where exactly do I say what roles a user has? I can't do it in the code, because new users will be added all the time. I understand I'll need to store that in the database, I just don't know where I need to tell the application once they log in and are on the site what roles they have.

Any help is appreciated.