Add support for custom serializers

[manast]

https://github.com/OptimalBits/bull/issues/1411

[godinja]

@manast any intention to get this developed?

We have a use case where we (ideally) need to pass Decimal.js types to downstream jobs in a flow.

[manast]

@godinja in your case, couldn't you just serialize the decimal.js types before adding the job data? In other words, it should be easy enough to build a custom serializer on top of the data object that supports your use case.

[ryanolf]

+1 to custom serialisers-- or at add an option for superjson.

[duckception]

+1