proc/worker/client.go
func (w *Worker) DecrementCurrentSupply(job *data.Job) error {
	logger := w.logger.Add("method", "DecrementCurrentSupply", "job", job)
	offering, err := w.relatedOffering(logger, job, data.JobDecrementCurrentSupply)
	if err != nil {
		return err
	}

	offering.CurrentSupply--

	err = data.Save(w.db.Querier, offering)
	if err != nil {
		logger.Error(err.Error())
		return ErrInternal
	}

	return nil
}
func (w *Worker) DecrementCurrentSupply(job *data.Job) error {
	logger := w.logger.Add("method", "DecrementCurrentSupply", "job", job)
	offering, err := w.relatedOffering(logger, job, data.JobDecrementCurrentSupply)
	if err != nil {
		return err
	}

	offering.CurrentSupply--

	err = data.Save(w.db.Querier, offering)
	if err != nil {
		logger.Error(err.Error())
		return ErrInternal
	}

	return nil
}
// DecrementCurrentSupply finds offering and decrements its current supply.