Consider removing default scope in Sortable
gitlab-org/gitlab-ce#23075 illustrates the perils of adding a default scope. For example, the ORDER BY can cause a significant performance issue by causing the SQL optimizer to use a non-ideal index.
I think we need to consider removing this default scope. It may be tricky to find which controllers/APIs depend on this at the moment.
/cc: @eReGeBe, @yorickpeterse