Simple but general django invoice application

Usage
---------

1. Add 'invoices' application in the ``INSTALLED_APPS`` settings:
   
	INSTALLED_APPS = (
	    # ...
	    'invoices',
	)

2. Add the poll's url to your urls.py.

	urlpatterns = patterns('',
		# ...
	    url(r'^invoices/', include('invoices.urls')),
	)

3. Run python manage.py migrate invoices to create DB tables (invoices use django-south).