How to change authentication query in Laravel?

I just learn Laravel a couple of days and I tried to use built-in Authentication. I want to change the id refered in query to user_id because in my database I use user_id instead of id. Where can I find that query so I can change it accordingly? At this moment I get SQLSTATE[42S22]: Column not found: 1054 Unknown column 'id' in 'where clause' (SQL: select * fromuserswhereid= 2 limit 1)

via Chebli Mohamed