[DISCUSSION] Per-claim optional processing

[victorolinasc]

Joken configuration now has a Joken.Claim struct which has a :options field. This came from the #182 PR. We could add custom messages, skipping the claim if some condition match and whatnot.

Ideas are welcome here.

[ybod]

There is two ways we can implement optional claims:

• pass nil or :not_defined atom into the validation function if claim is not defined at all. In this case the validation function will decide on the outcome.

• add an optional: [claim1, claim2...]parameter into the :options in case we do not want to fail if some claim is not defined at all, if this claim is defined it will be still validated

[victorolinasc]

On Joken 2 each claim might have its own options since now we use a "key" => %Joken.Claim{} config map. I think it is easier to add flags there. What do you say?