talks: add video link to GothamGo gRPC talk.

Change-Id: Ia749c318cbad40c15019cbc788897f491155da5f
Reviewed-on: https://go-review.googlesource.com/17077
Reviewed-by: Alan Donovan <adonovan@google.com>
diff --git a/2015/gotham-grpc.slide b/2015/gotham-grpc.slide
index c21792d..6f7d37f 100644
--- a/2015/gotham-grpc.slide
+++ b/2015/gotham-grpc.slide
@@ -6,6 +6,11 @@
 @Sajma
 sameer@golang.org
 
+* Video
+
+This talk was presented at GothamGo in New York City, October 2015.
+
+.link https://www.youtube.com/watch?v=vTIyz2QfExc&index=7&list=PLeGxIOPLk9ELh9tsPZMzau6CzMjfMzp9- Watch the talk on YouTube
 
 * RPC isn't just Remote Procedure Call