Impressions and clicks are only recorded when the user has a session

[ataylor32]

Oftentimes, anonymous users won't have a session. In that scenario, ads that are shown to them and ads that they click on won't be recorded. Django's SESSION_SAVE_EVERY_REQUEST setting won't help with this either. The render_ads_zone template tag and the AdClickView view both have this line:

if request.session.session_key:

That line could be replaced with something like this:

request.session['django-ads'] = True
request.session.save()

You could also have the app support both behaviors (if you wanted to) with a setting like ADS_SESSION_KEY. If it's a string, use the behavior I proposed above. If it's None, use the current behavior. Its default value could be 'django-ads'.

Thoughts?