diff --git a/go.mod b/go.mod
index 9257516b..474da3b8 100644
--- a/go.mod
+++ b/go.mod
@@ -38,6 +38,7 @@ require (
 	golang.org/x/net v0.0.0-20190827160401-ba9fcec4b297 // indirect
 	golang.org/x/sys v0.0.0-20190826190057-c7b8b68b1456 // indirect
 	golang.org/x/text v0.3.2 // indirect
+	google.golang.org/appengine v1.4.0 // indirect
 	google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55 // indirect
 	google.golang.org/grpc v1.23.0 // indirect
 	gotest.tools v2.2.0+incompatible // indirect