public function findUsersWithNoGroup()
    {
        $query = $this->find();

        return $query->leftJoin(
                [$this->UsersGroups->alias() => $this->UsersGroups->table()],
                [$this->aliasField('id') . ' = ' . $this->UsersGroups->aliasField('user_id')]
            )
            ->select([
                'Users.id',
                'group_count' => $query->func()->count('UsersGroups.group_id')
            ])
            ->group('Users.id')
            ->having('group_count = 0');
    }