title: "This field is required" when sending POST request to Django Rest Framework API
body: <p>I'm trying to create a new <code>Category</code>, which simply has <code>name</code> field to be filled up, but it insists on showing the error saying it's required.</p>
  
  <p><strong>models.py</strong>:</p>
  
  <pre><code>class Category(models.Model):
      name = models.CharField(max_length=32, unique=True)
      created_at = models.DateTimeField(default=timezone.now)
      updated_at = models.DateTimeField(default=timezone.now)
  
      def __str__(self):
          return self.name
  </code></pre>
  
  <p><strong>serializers.py</strong></p>
  
  <pre><code>class CategorySerializer(serializers.Serializer):
      id = serializers.IntegerField(required=False)
      name = serializers.CharField(max_length=32)
  
      def create(self, validated_data):
          return Category.objects.create(**validated_data)
  
      def update(self, instance, validated_data):
          pass
  </code></pre>
  
  <p><strong>views.py</strong></p>
  
  <pre><code>class CategoryList(APIView):
      def get(self, request):
          """
          Gets all the existing categories
          :param request:
          :return: Category
          """
          categories = Category.objects.all().filter().order_by("name")
          serializer = CategorySerializer(categories, many=True)
  
          return Response(serializer.data)
  
      def post(self, request):
          """
          Create one new category
          :param request:
          :return: Category
          """
          serializer = CategorySerializer(data=request.data)
  
          if serializer.is_valid():
              serializer.save()
  
              return Response(serializer.data, status=HTTP_201_CREATED)
  
          return Response(serializer.errors, status=HTTP_400_BAD_REQUEST)
  </code></pre>
  
  <p>Priting <code>request.data</code> shows me, for example: <code>{'data': {'name': 'Withdrawal'}}</code>. It shows the data are being sent and received but I don't understand why this errors shows up.</p>