introduce image-updater

image/overlay/etc/init.d/bubble

@@ -4,12 +4,6 @@ depend() {
 	need docker tsdns
 }
 
-start_pre() {
-    until docker pull git.sfclub.cc/cloud/workspace-image:latest; do
-        sleep 10
-    done
-}
-
 command="/usr/bin/bubble"
 command_args="-config /daemon/config.yaml 2>&1"
 pidfile="/run/${RC_SVCNAME}.pid"