public static function all()
    {
        global $wpdb;

        // Get the table name
        $table = static::get_table();

        // Get the items
        $results = $wpdb->get_results("SELECT * FROM `{$table}`");

        foreach ($results as $index => $result) {
            $results[$index] = static::create((array) $result);
        }

        return $results;
    }