Updating docs for usage of force=yes when performing a restore.

doc/raketasks/backup_restore.md

@@ -494,7 +494,7 @@ more of the following options:
 
 - `BACKUP=timestamp_of_backup` - Required if more than one backup exists.
   Read what the [backup timestamp is about](#backup-timestamp).
-- `force=yes` - Do not ask if the authorized_keys file should get regenerated.
+- `force=yes` - Does not ask if the authorized_keys file should get regenerated and assumes 'yes' for warning that database tables will be removed.
 
 ### Restore for installation from source