Update digit_recognition.ipynb

Note on forum post.

Author: adarsh0806

projects/digit_recognition/digit_recognition.ipynb

@@ -30,7 +30,7 @@
     "\n",
     "You can use Keras to implement your model. Read more at keras.io.\n",
     "\n",
-    "Here is an example of a [published baseline model on this problem](http://static.googleusercontent.com/media/research.google.com/en//pubs/archive/42241.pdf). ([video](https://www.youtube.com/watch?v=vGPI_JvLoN0))"
+    "Here is an example of a [published baseline model on this problem](http://static.googleusercontent.com/media/research.google.com/en//pubs/archive/42241.pdf). ([video](https://www.youtube.com/watch?v=vGPI_JvLoN0)). You are not expected to model your architecture precisely using this model nor get the same performance levels, but this more to show an exampe of an approach used to solve this particular problem. We encourage you to try out different architectures for yourself and see what works best for you. Here is a useful [forum post](https://discussions.udacity.com/t/goodfellow-et-al-2013-architecture/202363) discussing the architecture as described in the paper."
    ]
   },
   {