Pivot values to columns
Since MySQL doesn't allow FULL OUTER JOIN this is a bit trickier, but doable taking the week as main key for the left joins.

select distinct s.week, user1, user2, user3 from scorecards s left outer join 
(select week, score as user1 from scorecards where user = 1) a
on s.week = a.week left join
(select week, score as user2 from scorecards where user = 2) b
on s.week = b.week left join
(select week, score as user3 from scorecards where user = 3) c
on s.week = c.week
;