tilpner: configuration.nix is `import /home/jamie/code/nixos-configuration "my-hostname"`

And `default.nix` is 

```
device:
{ config, pkgs, lib, ... }:
let sources = import ./nix/sources.nix;
in {
  imports = [
    "${./hardware-configuration}/${device}.nix"
    "${sources.home-manager}/nixos"
    (import ./modules device)
  ];

  inherit device;

  system.stateVersion = "18.03";
}
```