[Roots] Update scratchpad bundle

example/scratchpad/bundle.js

@@ -33,6 +33,11 @@ define([
     legacyRegistry.register("example/scratchpad", {
         "extensions": {
             "roots": [
+                {
+                    "id": "scratch:root"
+                }
+            ],
+            "models": [
                 {
                     "id": "scratch:root",
                     "model": {