title: Using different authentication for different operations in ModelViewSet in Django REST framework
body: <p>I have the following ModelViewSet</p>
  
  <pre><code>class UserViewSet(viewsets.ModelViewSet):
      """
      API endpoint that allows users to be viewed or edited.
      """
      queryset = User.objects.all()
      serializer_class = UserSerializer
      authentication_classes = (TokenAuthentication,)
      permission_classes = (permissions.IsAuthenticated, MyUserPermissions)
  </code></pre>
  
  <p>I want the <code>create method (POST on /users/)</code> to not ask for any authentication. How can I override the authentication_classes in this case? I'm talking about <code>ModelViewSet</code> not generic API views. </p>