diff --git a/Dockerfile b/Dockerfile
index f186cfa9a0cc7164cfcc4af28c38cc1a4115a008..2a2ecca530d1215ac826f5e70ddba13cdd9a70c6 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -16,3 +16,4 @@ USER nobody
 CMD [ "supersonic", "/crontab" ]
 HEALTHCHECK CMD pgrep supersonic
 RUN supersonic -test /crontab
+ONBUILD RUN supersonic -test /crontab