Migration dependency setup

[cam-stitt]

Should be able to reference the dependency of each migration so that naming conventions are not important. Also assists with larger projects and conflicts of work being done.

This issue was raised in #26.

[hjc]

Do you have an idea for what you want here?

Sort of like:

__depends__ = ('al2iasdkzxc', 'asdl123023')  # these must be run first
__depended_on_by__ = ('foobar', 'bazquux')  # these must be run after this one

# my migration code here

Where if __depends__ is present, then those other migrations must be migrated first, but it's optional, and, if missing, we fall in line with the file naming conventions?

Or are you thinking of doing what Alembic does with up_revision, down_revision, and forcing users to maintain a single, linear path for migrations? (If so, that's my least favorite part about Alembic, so I'd request that we hide this behind a flag 😄).

[cam-stitt]

Yes, I was thinking along the line of just having a __depends__ style argument.