public function getKeywords()
    {
        $results = [];
        $data = $this->getData();
        $text = strip_tags($data['content']);
        $words = str_word_count($text, 1);
        foreach ($words as $word) {
            if (strlen($word) < 4) {
                continue;
            }
            if (! array_key_exists($word, $results)) {
                $results[$word] = 0;
            }
            $results[$word]++;
        }

        arsort($results);
        $results = array_slice(array_keys($results), 0, 20);
        return implode(', ', $results);
    }