anchor.diff:  let
     quassel = pkgs.quasselDaemon;
     cfg = config.services.quassel;
  +  user = if cfg.user != null then cfg.user else "quassel";
   in
   
   {
  
positive.code: 
          preStart = ''
              mkdir -p ${cfg.dataDir}
              chown ${cfg.user} ${cfg.dataDir}
          '';
  
          exec = ''
              ${pkgs.su}/bin/su -s ${pkgs.stdenv.shell} ${cfg.user} \
                  -c '${quassel}/bin/quasselcore --listen=${cfg.interface}\
                      --port=${toString cfg.portNumber} --configdir=${cfg.dataDir}'
          '';
  
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.
          '';
        };
  
  