schema.py

# cookbook/ingredients/schema.py
import graphene

from graphene_django.types import DjangoObjectType

from ingredients.models import Category, Ingredient


class CategoryType(DjangoObjectType):
    class Meta:
        model = Category


class IngredientType(DjangoObjectType):
    class Meta:
        model = Ingredient


class Query(object):
    hello = graphene.String()

    def resolve_hello(self, info, **kwargs):
        return "world"