ActiveRecordColumnTypes - Create a 'Mixed' option

[zack-freedman-shopify]

Referencing this page.

I'm wondering if we could create a new mixed option that is between nilable and untyped. If the only reason we mark columns as 'untyped' is non-nil fields might be nilable before save, there's no actual reason that truly nilable columns should be untyped.

I'm proposing a ActiveRecordColumnTypes called mixed:

• Non-nil fields continue to be untyped
• Nilable fields get typed consistently with persisted mode.

Another possible name might be untyped-only

[Morriar]

I think it's a good step between untyped and nilable 👍

Do you want to take a stab at it?