diff --git a/mendel-builder/Dockerfile b/mendel-builder/Dockerfile
index 67f53b7..688fb34 100644
--- a/mendel-builder/Dockerfile
+++ b/mendel-builder/Dockerfile
@@ -35,5 +35,7 @@
 
 RUN /bin/bash -c 'apt-get clean'
 
-VOLUME ["/var/lib/aptly", "/srv/aptly-publish-fs"]
+VOLUME [ "/var/lib/aptly" ]
+VOLUME [ "/srv/aptly-publish-fs" ]
+
 WORKDIR /var/lib/aptly