diff --git a/README.md b/README.md
index 7570fb1..162655f 100644
--- a/README.md
+++ b/README.md
@@ -52,6 +52,7 @@ This will build the site to the `build` folder. You can then start the server wi
 Clone the repository, then build a Docker image with:
 ```shell
 $ docker build -t not-nullptr/vert \
+	--build-arg PUB_ENV=production \
 	--build-arg PUB_HOSTNAME=vert.sh \
 	--build-arg PUB_PLAUSIBLE_URL=https://plausible.example.com .
 ```