✨ Add IntEnum type that allows storing values of enum as integers in database

[KunxiSun]

I add a IntEnum type decorator which I used in my private project.

I wish it helps!

import enum
class HeroStatus(enum.IntEnum):
    ACTIVE = 1
    DISABLE = 2    

from sqlmodel import IntEnum
class Hero(SQLModel):
    hero_status: HeroStatus = Field(sa_type=IntEnum(HeroStatus))


# Save as Integer in database, but load as IntEnum in program
user.hero_status == HeroStatus.ACTIVE      

[KunxiSun]

@KunxiSun: Yes - those are unrelated to your PR. We're looking into it here.

Thanks to let me know

[KunxiSun]

@KunxiSun, thanks for your interest and efforts!

I think this feature is quite useful. There seems to be no simple solution to configure int enums this way without creating custom TypeDecorator. This PR will provide such solution.

Please take a look at my in-code comments. Also, we need to update these tests to check statements for new field

Thanks for your code suggestion.
The statement tests are added.

I also changed the type from Integer to Small Integer, cuz I think the size of Integer is too large to be needed.

[YuriiMotov]

Looks interesting!
I think this feature is quite useful.
There seems to be no simple solution to configure int enums this way without creating custom TypeDecorator. This PR will provide such solution.

Implementation and tests look good to me.

We may want to describe this in docs, but maybe it's better to wait for Sebastian to validate the idea first