php artisan workbench vendor/package --resources
command is not available in laravel 5, but how now create package in laravel 5 ?
The laravel workbench has been renamed in laravel 5 to "Package Development" in the documentation
http://laravel.com/docs/master/packages
Notice that there is no longer a workbench command and you need to create your own package structure, as the Laravel creator want to limit the dependency between created packages and the Laravel framework (#ref)
UPDATE: Laravel 5 is now stable and the illuminate/workbench package can be used in a laravel 5 application as I suggested in this post