Update README.md

Author: DouglasAllen

README.md

@@ -6,3 +6,5 @@ All of the slides, answer files and other solutions used during the Introduction
 * https://mva.microsoft.com/en-US/training-courses/introduction-to-programming-with-python-8360?l=lqhuMxFz_8904984382
 
 * https://www.youtube.com/watch?v=tkMTkq-Is6E
+
+* https://microsoft.github.io/PTVS/