0.002000 Wed Oct 10 15:15:19 2018 +0700
 - Enhancement: add query_hosts method
 - Enhancement: add query_parent_hosts method
 - Enhancement: incur sorting overhead in set_app_attr() only in case of
   error
 - Bugfix: remove debug code and dependency on YAML::XS

0.001000 Sat Oct 6 10:56:10 2018 +0700
 - Initial release