append all files, but set only my folder in option

[KornetWeb]

Hellow. My project folder is '/var/www/html'. I want append files from '/var/www/html/vendor'. I set in option
Preloader::make() ->append([ROOT_PATH.'vendor/']) ->useRequire(ROOT_PATH.'vendor/autoload.php') ->writeTo('pathtofile');

where ROOT_PATH = '/var/www/html/`. When I start the script, out file set all files from /var/www/html. Why? May be I don't undestand readmy?