title: Django Rest Framework - One to Many relationship not working
body: <p><br>
  I'm trying to Serialize a Object that have Many Objects related. It's a Order has Many Logs relationship. I tried to do the same that in these tutorials (<a href="https://docs.djangoproject.com/en/2.1/topics/db/examples/many_to_one/" rel="nofollow noreferrer">https://docs.djangoproject.com/en/2.1/topics/db/examples/many_to_one/</a> and <a href="http://www.django-rest-framework.org/api-guide/relations/#nested-relationships" rel="nofollow noreferrer">http://www.django-rest-framework.org/api-guide/relations/#nested-relationships</a>) but it doesn't work. I have also looked in various google link but nothing. Anyone can help me, please? What I'm doing wrong?</p>
  
  <p><strong>models.py</strong></p>
  
  <pre><code>class MaintenanceOrder(models.Model):
      responsible_technician = models.ForeignKey(Technician, on_delete=models.DO_NOTHING, null=True)
  
      order_code = models.CharField(max_length=12, null=True)
      note_code = models.CharField(max_length=12, null=True)
      equipment = models.CharField(max_length=18, null=True)
      locale = models.CharField(max_length=30, null=True)
      short_description = models.CharField(max_length=40, null=False)
      description = models.TextField(null=True)
      priority = models.CharField(max_length=1, null=False)
      breakdown = models.CharField(max_length=1, null=True)
      stop_time = models.DateTimeField(null=True)
      end_time = models.DateTimeField(null=True)
  
      created_at = models.DateTimeField(auto_now_add=True)
      updated_at = models.DateTimeField(auto_now=True)
  
      status = models.ForeignKey(MaintenanceStatus, on_delete=models.DO_NOTHING)
  
      def __str__(self):
          return self.order_code
  
      class Meta:
          managed = True
  
  
  class MaintenanceLog(models.Model):
      maintenance_order = models.ForeignKey(MaintenanceOrder, on_delete=models.DO_NOTHING)
      technician = models.ForeignKey(Technician, on_delete=models.DO_NOTHING, blank=True, null=True)
  
      start_time = models.DateTimeField()
      stop_time = models.DateTimeField(null=True)
  
      description = models.TextField(null=True)
  
      created_at = models.DateTimeField(auto_now_add=True)
      updated_at = models.DateTimeField(auto_now=True)
  
      def __str__(self):
          return self.description
  
      class Meta:
          managed = True
  </code></pre>
  
  <p><strong>serializers.py</strong></p>
  
  <pre><code>class MaintenanceLogSerializer(serializers.ModelSerializer):
      class Meta:
          model = MaintenanceLog
          fields = '__all__'
  
  
  class MaintenanceOrderSerializer(serializers.ModelSerializer):
      status_code = serializers.IntegerField(source='status.status_code', read_only=True)
      order_log = MaintenanceLogSerializer(many=True, read_only=True)
  
      class Meta:
          model = MaintenanceOrder
          fields = '__all__'
  </code></pre>
  
  <p>This API it's returning all orders, but without "order_log"... Even if I specify "order_log" in fields, it doesn't return... Yes, there is related data in the database.</p>
  
  <p><strong>Additional Info</strong><br>
  Python: 3.5<br>
  Django: 2.1</p>