if the user does not exit, will create the user and invite he join the app
Merge branches 'auto-create-invitee' and 'dev' of github.com:xHFT/pencilme-dev into auto-create-invitee
add django-notification
add version number for django-notification
add notification after add invitee.
Merge pull request #11 from xHFT/notification

Notification