Business requirments:
- define max/min amount and max/min term (days)

Available operations are:
- apply_for_loan (term, amount)
- if application is not within amount/term range reject application
- if application is between 00:00 and 06:00 and max amount is asked then reject application
- cost of the issued loan is 10% of principal (not 10% per year)
- extend loan - (extension term is preconfigured. Upon extension the due date is changed, original due date + term)