core: properly handle invites; audit: log invite creation and usage

passbook/core/signals.py

@@ -0,0 +1,12 @@
+"""passbook core signals"""
+
+from django.core.signals import Signal
+
+# from django.db.models.signals import post_save, pre_delete
+# from django.dispatch import receiver
+# from passbook.core.models import Invite, User
+
+user_signed_up = Signal(providing_args=['request', 'user'])
+# TODO: Send this signal in admin interface
+invite_created = Signal(providing_args=['request', 'invite'])
+invite_used = Signal(providing_args=['request', 'invite', 'user'])