public function handle($data)
 {
     $this->validate_request(["assignment"]);
     $user = UserBackend::fetch_user_profile($this->params['id']);
     $assignment = Token::decode($data->{"assignment"});
     $data = UserBackend::add_user_assignment($user, $assignment);
     return $data;
 }
 public function handle($data)
 {
     $this->validate_request(["assignment"]);
     $group = GroupBackend::fetch_group_profile($this->params['id']);
     $users = GroupBackend::fetch_group_users($group);
     $assignmentId = Token::decode($data->{"assignment"});
     foreach ($users as $user) {
         UserBackend::add_user_assignment($user, $assignmentId);
     }
     $assignmentId = AssignmentBackend::fetch_assignment_profile($assignmentId);
     return ["assignment" => $assignmentId];
 }