bug #532 Support class inheritance in UserProvider::supportsClass by default (MisatoTremor)

This PR was merged into the 1.0-dev branch.

Discussion
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Support class inheritance in UserProvider::supportsClass by default

I propose to add the check if given class name is inherited from the User class (like the EntityUserProvider implementation does) to the UserProvider template.

Also I would follow up with a documentation PR reflecting that change in https://github.com/symfony/symfony-docs/blob/master/security/user_provider.rst

Or would it better to just add a info about this additional check to the documentation?

Commits
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fa83c95 Allow wrapper classes in supportsClass

Author: weaverryan

src/Resources/skeleton/security/UserProvider.tpl.php

@@ -59,7 +59,7 @@ public function refreshUser(UserInterface $user)
      */
     public function supportsClass($class)
     {
-        return <?= $user_short_name ?>::class === $class;
+        return <?= $user_short_name ?>::class === $class || is_subclass_of($class, <?= $user_short_name ?>::class);
     }
 <?php if ($password_upgrader): ?>