post https://api.voucherify.io/v1/loyalties/:campaignId/members
This method assigns a loyalty card to a customer. It selects a loyalty card (vouchers) suitable for publication, adds a publish entry, and returns the published voucher.
A voucher is suitable for publication when it's active and hasn't been published yet.
Auto-update campaign
In case you want to ensure the number of publishable codes increases automatically with the number of customers, you should use auto-update campaign.
Returns
Returns a publication object if a valid identifier was provided. The object will contain a single published voucher object.