diff --git a/Dockerfile b/Dockerfile
index b431957..3ef744c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM golang:1.11 as builder
+FROM golang:1.12 as builder
 WORKDIR /go/whoami
 COPY . .
 RUN make build
diff --git a/go.mod b/go.mod
index 1c5bc2d..7c249df 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,5 @@
 module github.com/containous/whoami
 
+go 1.12
+
 require github.com/gorilla/websocket v1.2.0