add permissions to pages response serializer

apps/authorization/api/v1/serializers.py

@@ -23,6 +23,16 @@ class PageSerializer(serializers.ModelSerializer):
             'code'
         ]
 
+    def to_representation(self, instance):
+        """ custom output of serializer """
+        representation = super().to_representation(instance)
+        representation['permissions'] = PermissionSerializer(
+            Permissions.objects.filter(page=instance),
+            many=True
+        ).data
+
+        return representation
+
 
 class PermissionSerializer(serializers.ModelSerializer):
     """ Serialize permissions """