Fix metric names
Created by: hacklschorsch
Fixes #95 (closed).
@exarkun What do I do about materialization? I just changed the materialized nix file by hand, that made it work. I only changed three strings, why is this so complicated
@exarkun Something about shell.nix
is funky - it currently requries a ./default.nix
that isn't there. Maybe it's supposed to require ./nix/default.nix
instead?