Add a default CMD to the base image

build.sh

@@ -18,7 +18,19 @@ docker run --rm \
 IMAGE=$CI_REGISTRY_IMAGE
 STAMP=$(date +%F)
 
-tar -cC rootfs --exclude './dev/**' . | docker import - $IMAGE:$STAMP
+tar -caf rootfs.tar.gz \
+    --directory rootfs \
+    --exclude './dev/**' \
+    --numeric-owner \
+    --transform 's,^\./,,' .
+
+cat > Dockerfile <<EOF
+FROM scratch
+ADD rootfs.tar.gz /
+CMD ["bash"]
+EOF
+
+docker build -t $IMAGE:$STAMP .
 
 docker push $IMAGE:$STAMP
 docker tag  $IMAGE:$STAMP $IMAGE:jessie