[Story] Add corrections

👤 **As a** user
🙏 **I want** to put in a correction of the account balance
🎯 **so that** the balance follows the real balance closely

### Acceptance Criteria :+1: / :-1:

1. If I put in a correction with a date and an amount, the system should compute forward with that sum and add every further change to it to get the new projected balances.
