title: Login user using memory provider in Symfony
body: <p>after installing FOSUserBundle, now Im trying to login with user/
  userpass but I still get the "Bad credentials" message. This is my
  security.yml:</p>
  
  <pre><code>security:
      encoders:
          Symfony\Component\Security\Core\User\User: plaintext
  
      role_hierarchy:
          ROLE_ADMIN:       ROLE_USER
          ROLE_SUPER_ADMIN: [ROLE_USER, ROLE_ADMIN, ROLE_ALLOWED_TO_SWITCH]
  
      providers:
          in_memory:
              users:
                  user:  { password: userpass, roles: [ 'ROLE_USER' ] }
                  admin: { password: adminpass, roles: [ 'ROLE_ADMIN' ] }
          fos_userbundle:
              id: fos_user.user_manager
  
      firewalls:
          main:
              pattern: ^/
              form_login:
                  provider: fos_userbundle
              logout:       true
              anonymous:    true
              #anonymous: ~
              #http_basic:
              #    realm: "Secured Demo Area"
  </code></pre>
  
  <p>Any idea?</p>
  
  <p>symfony 2.0.4</p>