add instructions to virtualbox

Signed-off-by: Jessica Frazelle <princess@docker.com>

virtualbox/Dockerfile

@@ -1,9 +1,38 @@
 # Run virtualbox in a container
 #
-# docker run -v /tmp/.X11-unix:/tmp/.X11-unix \
+# docker run -d \
+# 	-v /tmp/.X11-unix:/tmp/.X11-unix \
 #	-e DISPLAY=unix$DISPLAY \
+#	--privileged \
+#	--name virtualbox \
 #	jess/virtualbox
 #
+# On first run it will throw an error that you need to
+# recompile the kernel module with: /etc/init.d/vboxdrv setup
+#
+# Here is how you get it to work:
+# copy the files you need for the module from the container that
+# is currently running to your host
+#
+# first the script:
+# 	docker cp virtualbox:/etc/init.d/vboxdrv .
+#
+# then the src:
+# 	docker cp virtualbox:/usr/src/vboxhost-4.3.28 /usr/src/
+#
+# then the share
+# 	cp virtualbox:/usr/share/virtualbox /usr/share
+#
+# then run the script:
+# 	./vboxdrv setup
+#
+# it will recompile the module, you can then see it in lsmod
+#
+# then you can remove all the shit you copied
+# 	rm -rf /usr/src/vboxhost*
+# 	rm -rf /usr/share/virtualbox
+# 	rm vboxdrv
+#
 FROM debian:jessie
 MAINTAINER Jessie Frazelle <jess@linux.com>