Add extraCommands option in autoUpgrade, add example for enable and ntfyUrlFile

modules/nixos-upgrade.nix

@@ -15,26 +15,35 @@
       cd ${cfg.flake}
       git pull
       nix flake update --commit-lock-file
+      ${cfg.extraCommands}
       git push
     '';
   };
 in {
   options.system.autoUpgrade = {
-    # TODO: make sure flake is a local folder
+    # TODO: make sure system.autoUpgrade.flake is a local folder
     updateFlake = lib.mkOption {
       default = false;
       description = "Update lockfile of the flake.";
+      example = true;
+    };
+
+    extraCommands = lib.mkOption {
+      type = lib.types.nullOr lib.types.str;
+      description = "Extra commands to run during upgrade";
     };
 
     failureNotification = {
       enable = lib.mkOption {
         default = false;
         description = "Enable ntfy notification on upgrade failure.";
+        example = true;
       };
 
       ntfyUrlFile = lib.mkOption {
         type = lib.types.nullOr lib.types.path;
         description = "Environment file containing NTFY_URL";
+        example = "/etc/secrets/failureNotification.env";
       };
     };
   };