Symfony 3.4 - new security provider - symfony

Question

I try add provider.What I'm doing wrong.
I have entity class, and I would like to extend this class
namespace AppBundle\Service;
use AppBundle\Entity\Pracownik;
use Symfony\Component\Security\Core\User\UserInterface;
class Userek extends Pracownik implements UserInterface
{
public function getUsername()
{
return $this->getLogin();
}
public function getSalt()
{
// you *may* need a real salt depending on your encoder
// see section on salt below
return null;
}
public function getPassword()
{
return $this->getLogin();
}
public function getRoles()
{
return array('ROLE_PRACOWNIK');
}
public function eraseCredentials()
{
}
public function isSuperAdmin()
{
return false;
}
}
in security.yml i add
encoders:
AppBundle\Service\Userek: plaintext
providers:
pracownik_db_provider:
entity:
class: AppBundle\Service\Userek
property: login
firewalls:
main:
pattern: ^/
form_login:
provider: pracownik_db_provider
login_path: /login
check_path: /login_check
logout:
path: /logout
target: /login
When I try login, i got message:
The class 'AppBundle\Service\Userek' was not found in the chain configured namespaces AppBundle\Entity, FOS\UserBundle\Model"
If I implements Class Pracownik adding methods from the implemented class without creating an additional new class extending the Pracownik class - works

Answer 1

Try to move your Userek class to the AppBundle\Entity\ folder, because Doctrine expects to find model classes on that folder Entity\.
Just move AppBundle\Service\Userek.php to AppBundle\Entity\Userek.php and come back if you still get the error message.
If you want Doctrine use another folder to store your model classes or entities, you can find some help to do that here or on the full documentation Doctrine configurations.