the bins tables need a default value when creating new records during update

we can't supply the value directly (otherwise it would be incorrect to do the addition afterwards)

the missing default value was causing a bug when creating new records at
update time at lib/CPANio/Game/Regular/Releases.pm line 30:

    NOT NULL constraint failed: release_bins.count [for Statement "INSERT INTO release_bins ( author, bin) VALUES ( ?, ? )"]