title: create new does returns 'list' object has no attribute 'create'
body: <p>I am trying to create a autocomplete input which can create a new object. </p>
  
  <pre><code>class CellLineAutocomplete(autocomplete.Select2QuerySetView):
      create_field = 'cell_line_name'
      model = CellLine
      def has_add_permission(self, request):
          return True
  
      def get_queryset(self):
          if self.q:
              return CellLine.objects.filter(cell_line_name__icontains=self.q)
          return []
  
      def get_result_label(self, item):
          return item.cell_line_name
  </code></pre>
  
  <p>When clicking the <a href="https://i.stack.imgur.com/M6vVW.png" rel="nofollow noreferrer">create option</a> I receive the following error:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/Users/xy/.virtualenvs/z/lib/python3.6/site-packages/django/core/handlers/exception.py", line 41, in inner
      response = get_response(request)
    File "/Users/xy/.virtualenvs/z/lib/python3.6/site-packages/django/core/handlers/base.py", line 249, in _legacy_get_response
      response = self._get_response(request)
    File "/Users/xy/.virtualenvs/z/lib/python3.6/site-packages/django/core/handlers/base.py", line 187, in _get_response
      response = self.process_exception_by_middleware(e, request)
    File "/Users/xy/.virtualenvs/z/lib/python3.6/site-packages/django/core/handlers/base.py", line 185, in _get_response
      response = wrapped_callback(request, *callback_args, **callback_kwargs)
    File "/Users/xy/.virtualenvs/z/lib/python3.6/site-packages/django/views/generic/base.py", line 68, in view
      return self.dispatch(request, *args, **kwargs)
    File "/Users/xy/.virtualenvs/z/lib/python3.6/site-packages/dal/views.py", line 48, in dispatch
      return super(ViewMixin, self).dispatch(request, *args, **kwargs)
    File "/Users/xy/.virtualenvs/z/lib/python3.6/site-packages/django/views/generic/base.py", line 88, in dispatch
      return handler(request, *args, **kwargs)
    File "/Users/xy/.virtualenvs/z/lib/python3.6/site-packages/dal/views.py", line 116, in post
      result = self.create_object(text)
    File "/Users/xy/.virtualenvs/z/lib/python3.6/site-packages/dal/views.py", line 92, in create_object
      return self.get_queryset().create(**{self.create_field: text})
  AttributeError: 'list' object has no attribute 'create'
  </code></pre>
  
  <p>I access the <a href="https://github.com/yourlabs/django-autocomplete-light/blob/master/src/dal/views.py#L101" rel="nofollow noreferrer">code</a> of the autocomplete git repo:</p>
  
  <pre><code>def create_object(self, text):
      """Create an object given a text."""
      return self.get_queryset().get_or_create(
          **{self.create_field: text})[0]
  </code></pre>
  
  <p>and edited it to work for me:</p>
  
  <pre><code>def create_object(self, text):
      """Create an object given a text."""
      return self.model.objects.get_or_create(
          **{self.create_field: text})[0]
  </code></pre>
  
  <p>Is there a better way to solve my problem than by hacking the code? </p>
  
  <p>Thanks</p>