Add new field in admin product attribute

[Voring]

Hey,

I would like to add a new field here: http://prntscr.com/mdliq6

1 .Add a new column "new_field" to database table ps_attribute_lang with type of varchar(1000)

2. Add following line in file /classes/Attribute.php

public $new_field;

3. Add following line in the same file 
 

Quote

'new_field' =>           array('type' => self::TYPE_STRING, 'lang' => true, 'validate' => 'isGenericName', 'required' => true, 'size' => 2000),

 
after this line
 

'name' =>                array('type' => self::TYPE_STRING, 'lang' => true, 'validate' => 'isGenericName', 'required' => true, 'size' => 128),

And now I have a problem because I do not know what steps I should take further, can anyone help me?