Add script for making the ccache volume.

diff --git a/make-ccache-volume b/make-ccache-volume
new file mode 100755 (executable)
index 0000000..c79eaa1
--- /dev/null
+++ b/make-ccache-volume
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+docker volume create ccache
+id=$(docker run --mount source=ccache,target=/ccache -itd ubuntu-18.04-64 bash)
+docker exec $id mkdir /ccache/ubuntu-18.04-64
+docker exec $id chown carl /ccache/ubuntu-18.04-64
+docker kill $id