added boilerplate for cronjob

Joel Grunbaum

2021-08-31 5ce9b0c04ee5b5e9dc5b2ae9b99a70a4857ae666

 system_backup.sh

@@ -15,6 +15,7 @@
    --one-file-system \
    --exclude-caches \
    --exclude /var/cache \
    --exclude /backup \
    \
    ::"$(date +%F)" \
    /