adjust result

src/TerribleDev.Blog.Web/Posts/Optimizing-Heroku-Cache-For-JS-Monorepos.md

@@ -73,4 +73,16 @@ I wired up the script on the post install process of the install lifecycle. Basi
 }
 ```
 
-Now every time a developer runs `yarn install` they will compute the cache directories. When we push changes to prod we get much better cache hits across our yarn workspace
+Now every time a developer runs `yarn install` they will compute the cache directories. The result is a mutation to the `package.json` that looks like the following.
+
+```json
+{
+  "cacheDirectories": [
+    "node_modules",
+    "./packages/server/node_modules",
+    "./packages/worker/node_modules"
+  ],
+}
+```
+
+When we push changes to prod we get much better cache hits across our yarn workspace.