Merge remote-tracking branch 'github/develop' into develop

contrib/backup/functions

@@ -40,7 +40,7 @@ function backup_dir_create () {
 
 function backup_files () {
   echo "creating file backup..."
-  tar -czf ${BACKUP_DIR}/${TIMESTAMP}_zammad_files.tar.gz ${ZAMMAD_DIR}
+  tar -C / -czf ${BACKUP_DIR}/${TIMESTAMP}_zammad_files.tar.gz ${ZAMMAD_DIR#/}
   ln -sfn ${BACKUP_DIR}/${TIMESTAMP}_zammad_files.tar.gz ${BACKUP_DIR}/latest_zammad_files.tar.gz
 }