title: UpdateView is missing a QuerySet Error
body: <p>As of today, my <code>UpdateView</code> no longer works. Whenever I select the icon to edit an item I get the following error: </p>
  
  <pre><code>EntryUpdate is missing a QuerySet. Define EntryUpdate.model, EntryUpdate.queryset, or override EntryUpdate.get_queryset().
  </code></pre>
  
  <p>I have never had to have a QuerySet within my <code>UpdateView</code> before, so I am unsure why it is asking for one now. My understanding of the Generic <code>UpdateView</code> is that the self-query was built in, but I may be wrong. </p>
  
  <p>Any help would be much appreciated.</p>
  
  <p><strong>views.py</strong></p>
  
  <pre><code>class IndexView(generic.ListView):
      template_name = 'argent/index.html'
  
      # paginate_by = 10
  
      def get_queryset(self):
          return Entry.objects.all()
  
      def get_context_data(self, **kwargs):
  
          ctx = super(IndexView, self).get_context_data(**kwargs)
  
          # TODAY'S ENTRY
          ctx['entry_qs'] = Entry.objects.filter(date=today_date)
  
          # CURRENT SAVINGS TOTALS
          ctx['savings_qs'] = Savings.objects.filter(id=1)
  
          # MONTHLY TOTALS
  
          # November
          ctx['November16_qs'] = MonthYear.objects.filter(month='November')
          # December
          ctx['December16_qs'] = MonthYear.objects.filter(month='December')
          # January
          ctx['January17_qs'] = MonthYear.objects.filter(month='January')
          # February
          ctx['February17_qs'] = MonthYear.objects.filter(month='February')
          # March
          ctx['March17_qs'] = MonthYear.objects.filter(month='March')
          # # April
          # ctx['April_qs'] = MonthYear.objects.filter(month='April')
          # # May
          # ctx['May_qs'] = MonthYear.objects.filter(month='May')
  
          return ctx
  
  
  class DetailView(generic.DetailView):
      model = Entry
      template_name = 'argent/detail.html'
      #
      # def get_context_data(self, **kwargs):
      #     ctx = super(DetailView, self).get_context_data(**kwargs)
      #     ctx['savings_qs'] = Savings.objects.filter(id=1)
      #     return ctx
  
  
  class EntryCreate(CreateView):
      form_class = EntryForm
      template_name = 'argent/entry_form.html'
  
      def form_valid(self, form):
          if form.save(self):
              # total_euros_spent
              sum_euros = Entry.objects.aggregate(s=Sum('euros_sum')).get('s')
              sum_euros_f = "{0:.2f}".format(sum_euros)
  
              # total_dollars_spent
              sum_dollars = Entry.objects.aggregate(s=Sum('dollars_sum')).get('s')
              sum_dollars_f = "{0:.2f}".format(sum_dollars)
  
              # total_sum
              sum_savings = Entry.objects.aggregate(s=Sum('daily_savings_dollars')).get('s')
              sum_format = "{0:.2f}".format(sum_savings)
  
              # total_sum_format
              sum_abs_savings = Entry.objects.aggregate(s=Sum('daily_savings_dollars')).get('s')
              absolute = abs(sum_abs_savings)
              sum_abs = "{0:.2f}".format(absolute)
  
              Savings.objects.filter(id=1).update(total_savings=sum_format, total_savings_display=sum_abs,
                                                  total_spent_dollars=sum_dollars_f, total_spent_euros=sum_euros_f)
  
              return super(EntryCreate, self).form_valid(form)
  
          else:
              return self
  
  
  class EntryUpdate(UpdateView):
      form_class = EntryForm
      template_name = 'argent/entry_form.html'
  
      def form_valid(self, form):
          if form.save(self):
              # total_euros_spent
              sum_euros = Entry.objects.aggregate(s=Sum('euros_sum')).get('s')
              sum_euros_f = "{0:.2f}".format(sum_euros)
  
              # total_dollars_spent
              sum_dollars = Entry.objects.aggregate(s=Sum('dollars_sum')).get('s')
              sum_dollars_f = "{0:.2f}".format(sum_dollars)
  
              # total_sum
              sum_savings = Entry.objects.aggregate(s=Sum('daily_savings_dollars')).get('s')
              sum_format = "{0:.2f}".format(sum_savings)
  
              # total_sum_format
              sum_abs_savings = Entry.objects.aggregate(s=Sum('daily_savings_dollars')).get('s')
              absolute = abs(sum_abs_savings)
              sum_abs = "{0:.2f}".format(absolute)
  
              Savings.objects.filter(id=1).update(total_savings=sum_format, total_savings_display=sum_abs, total_spent_dollars=sum_dollars_f, total_spent_euros=sum_euros_f)
  
              return super(EntryUpdate, self).form_valid(form)
  
          else:
              return self
  </code></pre>
  
  <p><strong>urs.py</strong></p>
  
  <pre><code>urlpatterns = [
      url(r'^$', views.IndexView.as_view(), name='index'),
  
      url(r'entry/detail/(?P&lt;pk&gt;[0-9]+)/$', views.DetailView.as_view(), name='detail'),
  
      url(r'entry/add/$', views.EntryCreate.as_view(), name='entry-add'),
  
      url(r'entry/update/(?P&lt;pk&gt;[0-9]+)/$', views.EntryUpdate.as_view(), name='entry-update'),
  
  ]
  </code></pre>
  
  <p>template</p>
  
  <pre><code>{% if object_list %}
          {% for Entry in object_list %}
              &lt;div class="col-md-3 col-sm-4 col-xs-6"&gt;
                  &lt;div class="thumbnail" style="background: #ebebeb" &gt;
                      &lt;h3 align="center" style="font-weight: bold; color: #337ab7;"&gt;{{ Entry.date }}&lt;/h3&gt;
                      &lt;div class="caption"&gt;
                          &lt;h4 align="center" style="color: #FF5A09"&gt;€{{ Entry.euros_sum }}
  
                          &lt;!-- View Details --&gt;
                          &lt;a href="{% url 'argent:detail' Entry.id %}"&gt;&lt;button type="button" class="btn btn-link btn-lg"&gt;
                          &lt;span class="glyphicon glyphicon-info-sign" aria-hidden="true"&gt;&lt;/span&gt;
                          &lt;/button&gt;&lt;/a&gt;
  
                          &lt;!-- Update --&gt;
                          &lt;a href="{% url 'argent:entry-update' Entry.id %}"&gt;&lt;button type="button" class="btn btn-link btn-lg" style="padding: 0"&gt;
                          &lt;span class="glyphicon glyphicon-pencil" aria-hidden="true"&gt;&lt;/span&gt;
                          &lt;/button&gt;
                          &lt;/a&gt;
                          &lt;/h4&gt;
                      &lt;/div&gt;
                  &lt;/div&gt;
              &lt;/div&gt;
          {% endfor %}
          {% endif %}
  </code></pre>