Meta Class fields not inherited
This doesn't look like peewee to me.
 Nope - it's Marshmallow. My apologies.

Take two models that demonstrate inheritance:

```
class BaseSchema(Schema):
    """Base serializer."""
    id = fields.Integer(dump_only=True)
    created_at = fields.DateTime(dump_only=True)

    class Meta:
        ordered = True

class PersonSchema(BaseSchema):
    """Person serializer."""
    updated_at = fields.DateTime(dump_only=True)
    name = fields.String()
    email = fields.Email(required=True)
```

The `PersonSchema` schema inherits all the attributes of the `BaseSchema`, as expected. However, it does not seem to inherit the meta attributes (i.e. `ordered`). To ensure ordered output, it is necessary to include these two lines in every model:

```
class Meta:
    ordered = True
```

I don't know if this is something that could be solved or not (I'm not all that familiar with the implementation of these 'Meta' classes).
