public static function suggest($keyword, $limit = 20)
    {
        /** @var self[] $tags */
        $tags = self::find()
            ->where(['like', 'name', $keyword])
            ->orderBy('frequency DESC, name')
            ->limit($limit)
            ->all();

        $names = array();

        foreach ($tags as $tag) {
            $names[] = ['word' => Html::encode($tag->name)];
        }

        return $names;
    }