nixos/gancio: add sendmail to path, make cli easier to use (#395737)

  };

  config = mkIf cfg.enable {

    environment.systemPackages = [ cfg.package ];

    environment.systemPackages = [

      (pkgs.runCommand "gancio" { } ''

        mkdir -p $out/bin

        echo "#!${pkgs.runtimeShell}

          cd /var/lib/gancio/

          exec ${lib.getExe cfg.package} ''${1:---help}

        " > $out/bin/gancio

        chmod +x $out/bin/gancio

      '')

    ];

    users.users.gancio = lib.mkIf (cfg.user == "gancio") {

      isSystemUser = true;

          NODE_ENV = "production";

        };

        path = [

          # required for sendmail

          "/run/wrappers"

        ];

        preStart = ''

          # We need this so the gancio executable run by the user finds the right settings.

          ln -sf ${configFile} config.json