Nix cache is not documented

[steve-chavez]

Problem

There's no doc explaining how to use the Nix cache, when you do nix develop it will compile everything.

One has to hunt the echo commands from:

https://github.com/supabase/postgres/blob/1772a43e063d4c763b868fbcf88e95eeaf9c2d6b/docker/nix/Dockerfile#L3-L5

Then sudo pkill nix-daemon for Nix to pick the updated settings (ref)

Solution

Document this

[samrose]

It can be scripted in the flake too