diff --git a/Dockerfile b/Dockerfile
index 6019ff6a..8a516363 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -32,6 +32,7 @@ ENV APACHE_LOG_DIR /var/log/apache2
 ENV APACHE_LOCK_DIR /var/lock/apache2
 ENV APACHE_PID_FILE /var/run/apache2.pid
 
+ARG COMMIT
 ENV COMMIT_SHA=${COMMIT}
 
 EXPOSE 80