Asking for "@localhost's password"

Hi there! Not entirely sure if this is the right place to ask this, I’m
still pretty new to all this. I’ve been trying to get this software
running: GitHub - danbooru/danbooru: A taggable image board written in Rails. but I’ve been running
into a bit of a brick wall in the deployment step (see attached image).
After trying to deploy, it asks me to login to the user “@localhost”,
and rejects every password I try. I feel like there should be a name
before “@localhost”, but I’m a bit lost. I’ve been able to google and
figure out everything else up to this point.

thanks for your time