Add sqlalchemy.orm relationships between models

[iancleary]

https://fastapi.tiangolo.com/tutorial/sql-databases/#create-the-relationships

from sqlalchemy import Boolean, Column, ForeignKey, Integer, String
from sqlalchemy.orm import relationship

class User(Base):
	__tablename__ = "users"

	id = Column(Integer, primary_key=True, index=True)
    email = Column(String, unique=True, index=True)
    hashed_password = Column(String)
    is_active = Column(Boolean, default=True)

	lists = relationship("ListObject", back_populates="owner")


class ListObject(Base):
	...
	owner_id:int = Column(Integer, ForeignKey("users.id"))

	sections = relationship("SectionObject", back_populates="lists")


class SectionObject(Base):
	...
	list_id:int = Column(Integer, ForeignKey("lists.id"))
	
	items = relationship("ItemObject", back_populates="section")
	

class ItemObject(Base):
	...
	section_id:int = Column(Integer, ForeignKey("sections.id"))

[iancleary]

Added the question tag to see if I want to do this or not, so call it an idea to look into later