Unique attendee ID on data export

app/Http/Controllers/EventAttendeesController.php

@@ -591,6 +591,7 @@ class EventAttendeesController extends MyBaseController
                         'attendees.first_name',
                         'attendees.last_name',
                         'attendees.email',
+			'attendees.private_reference_number',
                         'orders.order_reference',
                         'tickets.title',
                         'orders.created_at',
@@ -607,6 +608,7 @@ class EventAttendeesController extends MyBaseController
                     'First Name',
                     'Last Name',
                     'Email',
+		    'Ticket ID',
                     'Order Reference',
                     'Ticket Type',
                     'Purchase Date',