some parts of product - fix custom pagination - add id to pages list

apps/product/web/api/v1/serializers.py

@@ -0,0 +1,27 @@
+from rest_framework import serializers
+from apps.product import models as product_models
+
+
+class ReferenceProductSerializer(serializers.ModelSerializer):
+    """ Serializer of reference product """
+
+    class Meta:
+        model = product_models.ReferenceProduct
+        fields = '__all__'
+
+
+class ProductSerializer(serializers.ModelSerializer):
+    """ Serializer of product """
+
+    class Meta:
+        model = product_models.Product
+        fields = '__all__'
+
+    def to_representation(self, instance):
+        """ Custom output of product serializer """
+
+        representation = super().to_representation(instance)
+        if instance.reference:
+            representation['reference'] = ReferenceProductSerializer(instance.reference).data
+
+        return representation