Having a distinct class just for that was a bit overkill

Rename classes to (hopefully) clearer names while we're doing that.

Remove superfluous lib: true, type: redis, service: true, models: true, services: true, no_db: true, api: true

Signed-off-by: Rémy Coutable <remy@rymai.me>

The initial commit doesn't have a parent, so explicitly pass the blank
SHA and handle that when calculating the position.