README: update deployment instructions a bit

Change-Id: Ibfe933596b0bb182915c569caf67e02d9d3dec24
Reviewed-on: https://go-review.googlesource.com/c/talks/+/200220
Reviewed-by: Andrew Bonventre <andybons@golang.org>

README

diff --git a/README b/README
index 597ee4c..3d1b968 100644
--- a/README
+++ b/README
@@ -7,6 +7,7 @@
 To deploy these talks to App Engine, copy the contents of tools/cmd/present to
 the root of this repository and run:
 
-	gcloud app deploy
+	rsync -a ../tools/cmd/present/ ./
+	gcloud --project=golang-org app deploy
 
 To submit changes to this repository, see http://golang.org/doc/contribute.html.