Notify people when their contacts sign up

[patrys]

The patch follows. What is left is to create the notification template.

diff --git a/friends/management.py b/friends/management.py
index 387a69c..76e8241 100644
--- a/friends/management.py
+++ b/friends/management.py
@@ -7,6 +7,7 @@ if "notification" in settings.INSTALLED_APPS:
     from notification import models as notification
     
     def create_notice_types(app, created_models, verbosity, **kwargs):
+        notification.create_notice_type("contact_joined", _("Contact Joined"), _("one of your contacts has joined the site"), default=2)
         notification.create_notice_type("friends_invite", _("Invitation Received"), _("you have received an invitation"), default=2)
         notification.create_notice_type("friends_invite_sent", _("Invitation Sent"), _("you have sent an invitation"), default=1)
         notification.create_notice_type("friends_accept", _("Acceptance Received"), _("an invitation you sent has been accepted"), default=2)
diff --git a/friends/models.py b/friends/models.py
index 03afcd5..9ebcc9b 100644
--- a/friends/models.py
+++ b/friends/models.py
@@ -226,8 +226,10 @@ if EmailAddress:
                     join_invitation.save()
                     # notification will be covered below
             for contact in Contact.objects.filter(email=instance.email):
-                contact.users.add(instance.user)
-                # @@@ send notification
+                if not instance.user in contact.users.all():
+                    contact.users.add(instance.user)
+                    if notification:
+                        notification.send([contact.user], "contact_joined", {"new_user": instance.user})
     
     # only if django-email-notification is installed
     signals.post_save.connect(new_user, sender=EmailAddress)