feat: add force modify mail and add student to courses

mongo/user.py

@@ -92,7 +92,7 @@ def batch_signup(
                 except engine.DoesNotExist:
                     new_user = cls.get_by_email(u['email'])
                 if force:
-                    new_user.force_update(u)
+                    new_user.force_update(u, course)
             registered_users.append(new_user)
         if course is not None:
             new_student_nicknames = {
@@ -103,7 +103,7 @@ def batch_signup(
             course.update_student_namelist(new_student_nicknames)
         return new_users
 
-    def force_update(self, new_user: Dict[str, Any]):
+    def force_update(self, new_user: Dict[str, Any], course: Optional[Course]):
         '''
         Force update an existent user in batch update procedure
         '''
@@ -113,6 +113,11 @@ def force_update(self, new_user: Dict[str, Any]):
             self.update(role=role)
         if (password := new_user.get('password')) is not None:
             self.change_password(password)
+        if (email := new_user.get('email')) is not None:
+            self.update(email=email,
+                        md5=hashlib.md5(email.encode()).hexdigest())
+        if course is not None:
+            self.update(add_to_set__courses=course.id)
         self.reload()
 
     @classmethod