frontend: update README.md with new deployment instructions

Change-Id: I01fc0052da2d8fd245d74209d10f9323d1f5a82f
Reviewed-on: https://go-review.googlesource.com/85037
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/README.md b/README.md
index 4b4f986..2fd7edc 100644
--- a/README.md
+++ b/README.md
@@ -64,10 +64,12 @@
 
 # Deployment
 
-(Googlers only) To deploy the front-end, use `play/deploy.sh`.
+```
+gcloud --project=golang-org --account=person@example.com app deploy frontend/app.yaml
+```
 
 ```
-gcloud --project golang-org app deploy sandbox/app-flex.yaml --no-promote
+gcloud --project=golang-org --account=person@example.com app deploy sandbox/app-flex.yaml --no-promote
 ```
 
 Use the Cloud Console's to set the new version as the default: