text: Title: InputObjectType fields from models
  Body: I've used a `MongoengineObjectType` class to define the schema from model.
  There's a way to use a reference model to define a `InputObjectType` or `AbstractType` class? Something like that:
  ```
  class UserFields(graphene.AbstractType):
  	class Meta:
  		model = model.User
  
  class User(graphene.ObjectType, UserFields):
  	pass
  
  class UserInput(graphene.InputObjectType, UserFields):
  	pass
  
  
  ```