Add class method for getting overdue Invoices
Only work with Invoices of current user in Invoices controller
Add isOverdue() methods to Invoice
Feed view with overdue invoices
Modify isOverdue() method in Invoice
Add more seed data
Add notification of overdue invoices in navigation
Add status indicator in invoice index
Merge branch 'develop' of github.com:johanbrook/dat076-webapps into develop