updating readme

Author: jeroenterheerdt

samples/features/sql-big-data-cluster/app-deploy/README.md

@@ -18,7 +18,7 @@ These samples demonstrates how you can deploy a simple Python app into SQL Serve
 
 |Sample|Description|
 |-|-|
-|__[addpy](addpy/)__|This sample takes two numbers and returns the sum|
+|__[addpy](addpy/)__|This sample takes two numbers and returns the sum. This sample also has detailed instructions on how to call apps through a RESTful web service.|
 |__[magic8ball](magic8ball/)__|Runs a [Magic 8-Ball](https://en.wikipedia.org/wiki/Magic_8-Ball)|
 
 ### R