$belongs_to ignores primary_key option

[tuupola]

With the following code:

class Car extends ActiveRecord\Model {
    static $belongs_to = array(
        array("alarm", "foreign_key" => "slug", "primary_key" => "slug")
    );
}

var_dump(Car::find($id)->alarm);

The generated query will be

SELECT * FROM `alarms` WHERE `id`='something' LIMIT 0,1

when it should be

SELECT * FROM `alarms` WHERE `slug`='something' LIMIT 0,1