Добавить PHPDoc

Как пример, файл `app/Core/Model.php`:
```php
/**
 * The table's primary key.
 *
 * @var string
 */
protected $id = 'id';

/**
 * Name of database table
 *
 * @var string
 */
protected $table;

/**
 * An array of field names that are allowed
 * to be set by the user in inserts/updates.
 *
 * @var array
 */
protected $fields = [];
```