Hi, lately I've been looking into converting my single speed dirt jumper into an 8 speed dirt jumper, and when i was looking at the frame I noticed there was no 5mm hole for the derailleur to be installed. So I was wondering if drilling a 5mm hole into the frame(so I can install the derailleur) would be a good idea. And if not, what would be the best way to attach the derailleur.

Thanks for your time,