Mention aefix in the README.
It's complete enough for people to use.
Change-Id: If279bc9410b7ce3874f2d2ab382085391fc69a7f
diff --git a/README.md b/README.md
index 168245f..90e0036 100644
--- a/README.md
+++ b/README.md
@@ -26,8 +26,10 @@
## Updating a Go App Engine app
-This section describes how to update a traditional Go App Engine app to use
-these packages.
+This section describes how to update an older Go App Engine app to use
+these packages. A provided tool, `aefix`, can help automate steps 2 and 3
+(run `go get google.golang.org/appengine/cmd/aefix` to install it), but
+read the details below since `aefix` can't perform all the changes.
### 1. Update YAML files (App Engine flexible environment / Managed VMs only)
