There are no commands defined in the "entrust" namespace

I'm using entrust for roles and I have to make the migrations, but when I want to execute php artisan entrust:migration I get this error

[Symfony\Component\Console\Exception\CommandNotFoundException] There are no commands defined in the "entrust" namespace.

"It will generate the _entrust_setup_tables.php migration."

What can I do? Thank you!

via Chebli Mohamed