title: Django RemoteUserBackend
body: <p>I'm trying to use multiple Authentication backends in Django 1.5.</p>
  
  <p>I want to use <code>RemoteUserBackend</code> with a custom <code>header</code> and the standard <code>ModelBackend</code></p>
  
  <p>Seems like I can make one or the other work, but not both. If I try to log in using <code>ModelBackend</code> i get this error:</p>
  
  <pre><code>"'CustomHeaderMiddleware' object has no attribute 'authenticate'" 
  </code></pre>
  
  <p>settings.py:</p>
  
  <pre><code>MIDDLEWARE_CLASSES = (
      ...
      'myapp.backends.custom_auth.CustomHeaderMiddleware',
      ...
  )
  
  AUTHENTICATION_BACKENDS = (
      'django.contrib.auth.backends.ModelBackend',
      'django.contrib.auth.backends.RemoteUserBackend',
      'myapp.backends.custom_auth.CustomHeaderMiddleware',
  )
  </code></pre>
  
  <p>custom_auth.py:</p>
  
  <pre><code>from django.contrib.auth.middleware import RemoteUserMiddleware
  
  class CustomHeaderMiddleware(RemoteUserMiddleware):
      header = "CUSTOM_USERID"
  </code></pre>
  
  <p>I'm not sure what I'm missing. It works if I set the 'CUSTOM_USERID', but I can't use the standard login.</p>
  
  <p>What am I missing?</p>