Reverse relation not returned from get_pydantic

[tscelsi]

Describe the bug
Hi! I am trying to get some ormar model tests up and running and to test the foreign key relation and reverse-relation functionality. Currently I have a very simple test file copied mainly from the ormar tests themselves. It looks something like this:

from test.settings import DATABASE_URL
from typing import Optional

import databases
import ormar
import sqlalchemy

metadata = sqlalchemy.MetaData()
database = databases.Database(DATABASE_URL, force_rollback=True)


class BaseMeta(ormar.ModelMeta):
    metadata = metadata
    database = database


class Person(ormar.Model):
    class Meta(BaseMeta):
        tablename = "person"

    id: int = ormar.Integer(primary_key=True)
    name: str = ormar.String(max_length=50)


class Pet(ormar.Model):
    class Meta(BaseMeta):
        tablename = "pet"

    id: int = ormar.Integer(primary_key=True)
    name: str = ormar.String(max_length=50)
    owner: Person = ormar.ForeignKey(Person, ondelete="CASCADE")


def test_fields_exist():
    assert 'owner' in Pet.get_pydantic().__fields__
    assert 'pets' in Person.get_pydantic().__fields__

My test simply asserts that both sides of the relation exist. That is that a pet has an owner and that a person can have some pets. Unfortunately, this test fails on the second assertion, there is no 'pets' pydantic field when calling get_pydantic() for Person. Maybe this is expected behaviour but some clarification on how it works would be nice (because I could have sworn that sometimes the 'pets' field appears when using get_pydantic).

To Reproduce
Steps to reproduce the behavior:

1. Copy above code, or look at test suite of ormar
2. run the test_fields_exist test

(Note: this should be a complete and concise piece of code that allows reproduction of an issue)

Expected behavior
Person get_pydantic() model should have a field 'pets' for the reverse-relation of the Pet foreign key.

Versions (please complete the following information):

• Database backend used (mysql/sqlite/postgress): aiosqlite v0.19.0
• Python version: 3.10.5
• ormar version: 0.12.2
• pydantic version: 1.10.8