Something is wrong with documentation or me. I do all what documentation says.
When i put in terminal :
$ php vendor/bin/doctrine orm:schema-tool:c
Uncomment the one of the following lines in bootstrap.php:
// or if you prefer yaml or XML
//$config = Setup::createXMLMetadataConfiguration(array(__DIR__."/config/xml"), $isDevMode);
//$config = Setup::createYAMLMetadataConfiguration(array(__DIR__."/config/yaml"), $isDevMode);
Which depends if you created yaml or xml meta config files...
Hope this helps.