Group operation contains incorrect behavior

[Scholablade]

Hello mr. agentm,

Your database project is incredible, I really enjoy learning and playing around with it, I tried using the Group operation however it's incorrect unlike the tutd tutorial. It duplicates data. Following the group with an ungroup is not the identity but an expansion of the duplicated data.

Am using the most recent docker image to use tutd.

I have written an issue in the github page.

Thanks,