This is the first question that came to my mind too. And it feels like a more accurate model of reality, since an anonymous user is a user, just without a username/password.
You could model this in other ways on the User model too, like having a registered_at column, which, when blank, means an unregistered user. (In case, for example, you wanted to autogenerate a username for anonymous users, for display purposes.)
You could model this in other ways on the User model too, like having a registered_at column, which, when blank, means an unregistered user. (In case, for example, you wanted to autogenerate a username for anonymous users, for display purposes.)