title: django - queryset in modelForm
body: <p>I need to filter <code>Food</code> model by datetime in <code>forms.py</code>, but I do not know how to do it. Could anyone help me?</p>
  
  <p>models.py</p>
  
  <pre><code>class Food(models.Model):
      class Meta:
          verbose_name = "Food"
          verbose_name_plural = "Foods"
  
      def __unicode__(self):
          return self.food_name
  
      food_name = models.CharField(verbose_name="Food Name", max_length=50)
      serve_date = models.DateTimeField(verbose_name="Serve Date")
  </code></pre>
  
  <p>forms.py</p>
  
  <pre><code>class Reserve(forms.ModelForm):
      food_name = forms.ModelChoiceField(
          queryset=Food.objects.all(), 
          widget=forms.Select(), 
          empty_label=u"برای انتخاب غذا کلیک کنید",
          )
  
      class Meta:
          model = Reservation
          fields = ('food_count', 'food_name')
  </code></pre>