Add cronjob Mode For The Docker Container

fixes #907

docker/entrypoint.sh

@@ -44,6 +44,14 @@ case "$1" in
   	exec /usr/bin/weed $@ $ARGS
 	;;
 
+  'cronjob')
+	MASTER=${WEED_MASTER-localhost:9333}
+	CRON_SCHEDULE=${CRON_SCHEDULE-*/5 * * * * *}
+	echo "$CRON_SCHEDULE" 'echo "volume.fix.replication" | weed shell -master='$MASTER > /crontab
+	echo "Running Crontab:"
+	cat /crontab
+	exec supercronic /crontab
+	;;
   *)
   	exec /usr/bin/weed $@
 	;;