Add comments and upgrade some stuff

scripts/backup

@@ -18,6 +18,10 @@ source /usr/share/yunohost/helpers
 # MANAGE SCRIPT FAILURE
 #=================================================
 
+ynh_clean_setup () {
+	### Remove this function if there's nothing to clean before calling the remove script.
+	true
+}
 # Exit if an error occurs during the execution of the script
 ynh_abort_if_errors
 
@@ -73,7 +77,7 @@ ynh_backup "/etc/logrotate.d/$app"
 ynh_backup "/etc/systemd/system/$app.service"
 
 #=================================================
-# BACKUP THE CRON FILE
+# BACKUP A CRON FILE
 #=================================================
 
 ynh_backup "/etc/cron.d/$app"