{pkgs, ...}: {
  # Let 'nixos-version --json' know about the Git revision
  # of this flake.
  system.configurationRevision = nixpkgs.lib.mkIf (self ? rev) self.rev;

  # Network configuration.
  networking.firewall.allowedTCPPorts = [80];

  # Enable a web server.
  services.httpd = {
    enable = true;
    adminAddr = "morty@example.org";
  };
}