nixos-config/modules/system/services/server/socialserver/spacebar/user/default.nix

{ config, lib, ... }:
{
  users = lib.mkIf config.system.socialserver.enable {
    users.spacebar = {
      group = "spacebar";
      isSystemUser = true;
      uid = 138;
    };
    groups.spacebar = {};
  };
}