title: Average of M2M element in ListView
body: <p>This is my model:</p>
  
  <pre><code>class FruitItem(models.Model):
      vote = models.IntegerField()
  
  class Fruit(models.Model):
     name = models.CharField(max_length=77)
     items = models.ManyToManyField(FruitItem)
  </code></pre>
  
  <p>This is my views:</p>
  
  <pre><code>class LoginRequiredMixin(object):
      @method_decorator(login_required)
      def dispatch(self, request, *args, **kwargs):
          return super(LoginRequiredMixin, self).dispatch(request, *args, **kwargs)
  
  class FruitsList(LoginRequiredMixin, ListView):
      template_name = 'fruits.html'
      context_object_name = "fruits"
      paginate_by = "8"
  
      def get_queryset(self):
          return Fruit.objects.filter(user=self.request.user).annotate(
                              vote_avg=Avg('items__vote'))
  </code></pre>
  
  <p>and template:</p>
  
  <pre><code>{% for f in fruits %}
      {{ f.name }}
      {{ f.items.vote_AVERAGE }}
  {% endfor %}
  </code></pre>
  
  <p>How can I display <code>vote</code> average for every list element?(<code>{{ f.items.vote}}</code>)</p>