anchor.diff:  
     config = mkIf cfg.enable {
   
  -    users.extraUsers = singleton
  +    users.extraUsers = mkIf (cfg.user == null) [
         { name = cfg.user;
           description = "Quassel IRC client daemon";
  -      };
  +      }];
       
   
       jobs.quassel =
  
positive.code: let
    quassel = pkgs.quasselDaemon;
    cfg = config.services.quassel;
  in
  
  {
  
negative.code:       };
  
        dataDir = mkOption {
          default = ''/home/${user}/.config/quassel-irc.org'';
          description = ''
            The directory holding configuration files, the SQlite database and the SSL Cert.
          '';
        };
  
        user = mkOption {
          default = null;
          description = ''
            The existing user the Quassel daemon should run as. If left empty, a default "quassel" user will be created.
          '';
        };
  
  