diff --git a/sites/005-hugo-extended/git-auto-pull/Dockerfile b/sites/005-hugo-extended/git-auto-pull/Dockerfile
index 2c328ae..a152944 100644
--- a/sites/005-hugo-extended/git-auto-pull/Dockerfile
+++ b/sites/005-hugo-extended/git-auto-pull/Dockerfile
@@ -5,7 +5,8 @@ RUN apk add --no-cache git openssh-client
 ADD pull.sh entrypoint.sh /
 RUN chmod +x pull.sh entrypoint.sh
 
-RUN echo "*/2 * * * * /pull.sh" > crontab.txt
+ARG INTERVAL=2
+RUN echo "*/${INTERVAL} * * * * /pull.sh" > crontab.txt
 RUN crontab crontab.txt
 
 WORKDIR /repo