If you’re using Django<=1.6 I’d recommend Kamagatos solution: just import your signals at the end of your models module.
For future versions of Django (>=1.7), the recommended way is to import your signals module in your app’s config ready() function:
my_app/apps.py
from django.apps import AppConfig
class MyAppConfig(AppConfig):
name="my_app"
def ready(self):
import my_app.signals
my_app/__init__.py
default_app_config = 'my_app.apps.MyAppConfig'