* Update client paid to date job:
* Backup Invoice HTML when invoice is marked as sent and paid
* Store HTML of invoice when invoice was paid
* Fix foreign keys in db schema
* V2 Endpoints for Company Migrations
* Fixes for tests
* Fixes for Store Payment Validation
* Tests for Payments
* Use custom validator to ensure payments are made ONLY to payable invoices
* Working on custom payment validators
* Update Client balance
* fixes for client balance
* Fixes for activity API
David Bomba