Updated readme

Author: barteksekula

README.md

@@ -324,10 +324,23 @@ You need to subscribe to a special event in order to know once content has been
 In this repo the subscription is already done in [onContentSaved.ts](src%2Fhelpers%2FonContentSaved.ts)
 
 ```ts
-epi.subscribe("contentSaved", function (message: ContentSavedEventArgs) {
-    // your code here
+window.addEventListener("optimizely:cms:contentSaved", (event: any) => {
+	const message = event.detail as ContentSavedEventArgs;
 });
 ```
 
+where is defined as following:
+
+```ts
+interface ContentSavedEventArgs {
+    contentLink: string;
+    previewUrl: string;
+    isIndexed: boolean;
+    properties: PropertySaved[];
+    parentId?: string;
+    sectionId?: string;
+}
+```
+
 More details here:
 https://docs.developers.optimizely.com/content-management-system/v1.0.0-CMS-SaaS/docs/enable-live-preview#refresh-the-applications-view-when-content-has-changed