public function getActiveList()
    {
        return $this->find()
            ->select(['id', 'first_name', 'last_name'])
            ->where([sprintf('%s.active', $this->getAlias()) => true])
            ->order(['username' => 'ASC'])
            ->formatResults(function (ResultSet $results) {
                return $results->indexBy('id')->map(function (User $user) {
                    return $user->first_name . ' ' . $user->last_name;
                });
            })
            ->cache(sprintf('active_%s_list', $this->getTable()), $this->getCacheName());
    }