Added scan repository bean to service test config
Added scan service test
Added no items in stock exception
Scan service now throws no items in stock exception
Fixed scan service test
Added status enumeration for scan entity which has two values PAID and UNPAID
Added payAllDebt service for user to pay all his debt at once
Added reminder service that will send out emails for users who owe money
Scan repository now can find all scans for user by it's email
pay all debt service now changes status of user scan's to PAID