diff --git a/common.debian b/common.debian
index 4f91915..042e4cb 100644
--- a/common.debian
+++ b/common.debian
@@ -1,12 +1,13 @@
-RUN REPO=http://cdn-fastly.deb.debian.org && \
-  echo "deb $REPO/debian jessie main\ndeb $REPO/debian jessie-updates main\ndeb $REPO/debian-security jessie/updates main" > /etc/apt/sources.list
-
 # Image build scripts
 COPY imagefiles/install-gosu-binary.sh /buildscripts/
 
 ARG DEBIAN_FRONTEND=noninteractive
+ARG REPO=http://cdn-fastly.deb.debian.org
 
 RUN \
+  bash -c "echo \"deb $REPO/debian jessie main\" > /etc/apt/sources.list"  && \
+  bash -c "echo \"deb $REPO/debian jessie-updates main\" >> /etc/apt/sources.list"  && \
+  bash -c "echo \"deb $REPO/debian-security jessie/updates main\" >> /etc/apt/sources.list" && \
   apt-get update --yes && \
   apt-get install --no-install-recommends --yes \
     automake \