adding layout resource - prerequisites

Author: henrymbuguakiarie

articles/active-directory/develop/tutorial-v2-android.md

@@ -35,6 +35,7 @@ In this tutorial:
 
 - [Android Studio](https://developer.android.com/studio)
 - [Android documentation on generating a key](https://developer.android.com/studio/publish/app-signing#generate-key)
+- [Layout resource](https://developer.android.com/guide/topics/resources/layout-resource)
 
 ## How this tutorial works