Revert "Revert "Use DB to store last-seen data, so it will presist across restarts""
Revert "Revert "Use DB to store last-seen data, so it will presist across restarts""

This reverts commit 8bfff07f7e5f528acc1ef217719bbf2ff92a3054.
So I'll actually have the code to fix

Uname-a/knife_scraper,Uname-a/knife_scraper,Uname-a/knife_scraper