Pull Request 

Please fix indention 
```php
public $validation =array(
    'username' => array(
        'length' => array(
            'validate_between', self::MIN_VALUE, self::USERNAME_MAX_VALUE,
        ),
    ),
    'body' => array(
        'length' => array(
            'validate_between', self::MIN_VALUE, self::BODY_MAX_VALUE,
        ),
    ),
);
```