Issue with _primary_key

[huzzi]

I think there is an issue with primary key when it's called something else other than "id"

protected static $_primary_key = array('user_id');

Fuel\Core\Database_Exception [ 1054 ]: Unknown column 't0.id' in 'field list' [ SELECT COUNT(t0.id) AS count_result FROM users AS t0 WHERE t0.username = 'wwwe' ]

http://fuelphp.com/forums/topics/view/1041