app/appengine: update app.yaml and README.md to account for service

This app is now running as a service called "build" instead of
on a named version in the default service. Update the app.yaml and
deployment instructions to account for this.

Change-Id: I5d68128e89bad6782982380b2012300a492ddb34
Reviewed-on: https://go-review.googlesource.com/c/build/+/191975
Reviewed-by: Alexander Rakoczy <alex@golang.org>
diff --git a/app/appengine/README.md b/app/appengine/README.md
index e2d2854..47dd42e 100644
--- a/app/appengine/README.md
+++ b/app/appengine/README.md
@@ -20,14 +20,11 @@
 
 ```sh
 gcloud config set project golang-org
-gcloud app deploy --no-promote -v {build|build-test} app.yaml
+gcloud app deploy app.yaml
 ```
 
 or, to not affect your gcloud state, use:
 
 ```
-gcloud app --account=username@google.com --project=golang-org deploy --no-promote -v build app.yaml
+gcloud app --account=username@google.com --project=golang-org deploy app.yaml
 ```
-
-Using -v build will run as build.golang.org.
-Using -v build-test will run as build-test.golang.org.
diff --git a/app/appengine/app.yaml b/app/appengine/app.yaml
index 7a6ab93..785cd3f 100644
--- a/app/appengine/app.yaml
+++ b/app/appengine/app.yaml
@@ -1,14 +1,15 @@
 runtime: go
 api_version: go1.9
+service: build
 
 handlers:
-- url: /static
-  static_dir: static
-  secure: always
-- url: /(init|buildtest|key|perflearn|_ah/queue/go/delay)
-  script: _go_app
-  login: admin
-  secure: always
-- url: /.*
-  script: _go_app
-  secure: always
+  - url: /static
+    static_dir: static
+    secure: always
+  - url: /(init|buildtest|key|perflearn|_ah/queue/go/delay)
+    script: _go_app
+    login: admin
+    secure: always
+  - url: /.*
+    script: _go_app
+    secure: always