diff --git a/updater/Dockerfile b/updater/Dockerfile
index 5d6eb3c..996251e 100644
--- a/updater/Dockerfile
+++ b/updater/Dockerfile
@@ -20,6 +20,7 @@ RUN apt-get update && \
     rm -rf /var/lib/apt/lists/*
 
 # Add user to the docker group
+ARG DOCKER_GID
 RUN usermod -aG $DOCKER_GID www-data
 
 # Create .docker directory and set permissions