Cannot upload images in Django Models

Hello I have a project where I want user to upload a title and body text and a picture named question, however when I submit the form only the title and body are saved the picture not. I changed the form tag in my template but it didn't help. Thanks in advance.

models.py    

class Question(models.Model):
    author = models.ForeignKey(User, on_delete= models.CASCADE,related_name='question_author')
    question=models.ImageField(upload_to='question/',blank=True,name="question")
    created_on = models.DateTimeField(auto_now_add=True)
    slug = models.SlugField(max_length=20, unique=True)
    title = models.CharField(max_length=128)
    body = models.CharField(max_length=400)

    class Meta:
        ordering = ['-created_on']

    def save(self, *args, **kwargs):
        self.slug = self.slug or slugify(self.title)
        super().save(*args, **kwargs)


    def __str__(self):
        return self.title


class Answer(models.Model):
    author = models.ForeignKey(User, on_delete= models.CASCADE,related_name='answer_author')
    question = models.ForeignKey('Question', on_delete=models.CASCADE, related_name='question_answer')
    answer=models.ImageField(upload_to='question/',blank=True)
    created_on = models.DateTimeField(auto_now_add=True)
    body = models.CharField(max_length=400)

    class Meta:
        ordering = ['-created_on']


    def get_absolute_url(self):
        return reverse("comment_detail",kwargs={'pk':self.pk})

forms.py

class QuestionForm(forms.ModelForm):
    class Meta:
        model=Question
        fields=['question','author','title','body']

class AnswerForm(forms.ModelForm):
    class Meta:
        model=Answer
        fields=['author','answer','body']

views.py

class QuestionDetail(FormMixin, generic.DetailView):
    model = Question
    template_name = 'question_detail.html'
    context_object_name = 'question'
    form_class = AnswerForm

    def get_context_data(self, **kwargs):
        context = super(QuestionDetail, self).get_context_data(**kwargs)
        context ['anwsermodel_list'] = Answer.objects.filter(question=self.object).order_by('created_on')
        context['form'] = AnswerForm(initial={'question': self.object})
        return context

    def post(self, request, *args, **kwargs):

question.html

       {%if user.is_authenticated%}
             <form method="post" style="margin-top: 1.3em;">
                 {% csrf_token %}
         <label for="post">Başlık:</label>
         <br>
         <input type="text" name="title" size=50 maxlength="128">
                 <br><br>
                 <label for="body">Soru:</label>
                 <br>
                 <textarea id="textarea" maxlength="400" name="body" rows="8" cols="50"></textarea>
                 <div id="textarea_feedback"></div>
                 <br>
                 <input type="file" name="question" accept="image/*" id="id_question">
                 <div class="modal-footer">
                     <button type="submit" class="btn btn-primary">Paylaş</button>
                     <button type="submit" class="btn btn-secondary" data-dismiss="modal">Kapat</button>
                 </div>
             </form>
       {%else%}
       <p style="text-align:center;">Soru sormak için <a style="text-decoration:none;" href="{% url 'account:login' %}?next={{ request.path }}">Giriş</a> yapmalısın.</p>
       {% endif %}
         </div>

I changed the form part from my template to {{form}} where I could see the form and submit it but again the picture were not uploaded.