fix(tuna, moodle-dl): create groups for users

modules/moodle-dl.nix

@@ -56,6 +56,7 @@ in {
     users.users.moodle-dl = {
       isSystemUser = true;
       home = cfg.directory;
+      group = "moodle-dl";
     };
 
     users.groups.moodle-dl = {};

modules/tuna.nix

@@ -76,7 +76,11 @@ in {
   };
 
   config = mkIf cfg.enable {
-    users.extraUsers.tuna.isSystemUser = true;
+    users.users.tuna = {
+      isSystemUser = true;
+      group = "tuna";
+    };
+    users.groups.tuna = {};
     # ref https://github.com/florianheinemann/MPD.FM/blob/9d037cf87597b26ae2f10ba9feea48946ad6cc68/service/MPD.FM.service
     systemd.services.tuna = {
       wantedBy = [ "multi-user.target" ];