Add Enum generation for Django choice fields

[jaydenwindle]

It would be great to support generating enum return types for Django CharFields where choices are defined. Currently strawberry resolves all CharField values to a String type.

We'll need to make sure that we don't define duplicate enum types or use names that would clash with other types in the schema.

See graphql-python/graphene-django#185 (comment) for a discussion about auto-generated choice enum types in Graphene.

[agritheory]

Does this have to be Django specific? A choice-to-enum pattern/utility would be helpful regardless of framework or database.

[patrick91]

@agritheory we do support python enums already! See here: https://github.com/strawberry-graphql/strawberry/blob/master/tests/test_enum.py

I've asked a friend to work on the design for the new website+docs so hopefully we'll start working on documentation soon :)

[patrick91]

Closing as we have this https://github.com/strawberry-graphql/strawberry-graphql-django :D