Possible to UPDATE array[] columns?

Using SQL is it possible to UPDATE (append) onto an array[] column. For
example say I have a column named "scores int[]".

ID  | scores
2   | {54,14,21,8}
3   | {12,0,7}

Now I want to append the score of 12 on row:ID 2 so the new scores would
read {54,14,21,8,12}. I thought maybe simply leaving the array key empty
would auto-append "UPDATE table set scores[] = 12 WHERE id = 2", not so....

Thanks!