hosts = { ... } doesn't work if /etc/hosts is not writable

[zoechi]

This should be added to the docs womewhere:

To make hosts (hostctl) work in NixOS this setting is required. It changes /etc/hosts to be writable for root.

environment.etc.hosts.mode = "0644";

[domenkozar]

Yeah, we should emit that error, could you make a PR?

[ParetoOptimalDev]

I had to delete the .devenv folder for this to work for some reason. But it works after:

1. make /etc/hosts writeable
2. delete projects .devenv folder
3. devenv up
4. devenv shell ping myhostname