added chapter 7

Author: mahmoudparsian

README.md

@@ -1,5 +1,8 @@
 # [Data Algorithms with Spark](https://www.oreilly.com/library/view/data-algorithms-with/9781492082378/)
 
+### The goal of this book is to enable 
+### writing simpler code for data algorithms
+
 * Author: [Mahmoud Parsian](https://www.linkedin.com/in/mahmoudparsian/) 
 * Email: [email protected]
 * This new book (to be published by O'Reilly) is the 2nd Edition of