Fix person_required with support for anonymous users

Addition to MR #110

aleksis/core/decorators.py

@@ -11,5 +11,5 @@ def admin_required(function: Callable = None) -> Callable:
 def person_required(function: Callable = None) -> Callable:
     """ Requires a logged-in user which is linked to a person. """
 
-    actual_decorator = user_passes_test(lambda u: user.person is not None)
+    actual_decorator = user_passes_test(lambda u: not u.is_anonymous and u.person is not None)
     return actual_decorator(login_required(function))