Updated Injecting code to UT Pages (markdown)

Injecting-code-to-UT-Pages.md

@@ -83,3 +83,17 @@ return (
         </ExtensionRoot>
     );
 ```
+
+## AddAllButton
+
+```ts
+// Existing code above
+    return ReactDOM.createPortal(
+        <ExtensionRoot>
+            <Button variant='filled' color='ut-burntorange' onClick={extractCoursesFromCalendar}>
+                Add Courses to UT Registration+
+            </Button>
+        </ExtensionRoot>,
+        container
+    );
+```