Update README.md

Author: iaman877

README.md

@@ -7,6 +7,7 @@
      1. [Dictionary](https://github.com/iaman877/Programming-with-Python/tree/master/Data%20Structure/Dictionary)
      1. [set](https://github.com/iaman877/Programming-with-Python/tree/master/Data%20Structure/set)
 1. [Control statement](https://github.com/iaman877/Programming-with-Python/tree/master/Control%20Statement/Loop%20with%20break)
+1. [String](https://github.com/iaman877/Programming-with-Python/tree/master/Stringk)
 
 
 ## Why python?