How do we add games to Grouvee that can't be added to IGDB?

I wanted to add a game from Steam called “Maitetsu” to my wishlist in Grouvee but it’s not in the database. Before, I was able to add new game entries to Grouvee but it looks like this option has been removed in favor of auto-importing entries from IGDB. However, some adult games can’t be added to IGDB such as this one:

https://www.igdb.com/games/maitetsu

Is there a workaround?
Or if not, can I get back the ability to add games manually to Grouvee for edge cases like these?