Add note about host-dir in VOLUME (cherry picked from commit f2fff9d913a8ab0436dd56033189a7c3713a59a2) Signed-off-by: Sebastiaan van Stijn <github@gone.nl> (cherry picked from commit 8fd6547fc3eb67e7efa7efb007ae6a4494cd2bb3) Signed-off-by: Tibor Vass <tibor@docker.com>