title: django count of foreign key model
body: <p>Hi i want to display a count of answers to my question model</p>
  
  <p>my model:</p>
  
  <pre><code>class Question(models.Model):
  
      text = models.TextField()
      title = models.CharField(max_length=200)
      date = models.DateTimeField(default=datetime.datetime.now)
      author = models.ForeignKey(CustomUser)
      tags = models.ManyToManyField(Tags)
  
      def __str__(self):
          return self.title
  
  
  class Answer(models.Model):
  
      text = models.TextField()
      date = models.DateTimeField(default=datetime.datetime.now)
      likes = models.IntegerField(default=0)
      author = models.ForeignKey(CustomUser)
      question = models.ForeignKey(Question)
  </code></pre>
  
  <p>my view:</p>
  
  <pre><code>def all_questions(request):
  
      questions = Question.objects.all()
      answers = Answer.objects.filter(question_id=questions).count()
  
      return render(request, 'all_questions.html', {
              'questions':questions, 'answers':answers })
  </code></pre>
  
  <p>Right now view displays count of all answers. How can i filter it by the <code>Question</code> model? </p>