Can you change it to `iid` please?  I made `iid` for per project id (for issues and MR).

See https://github.com/gitlabhq/gitlabhq/commit/125c07fa0aa31e6c83c8fcc90df623c2ef85832f
and https://github.com/gitlabhq/gitlabhq/commit/7047a44a26f0f75ab23c58c47d096060c01256ed