Merge branch 'active-observers' into 'dev'

Exclude observers with no observations

See merge request librespacefoundation/satnogs/satnogs-network!491

network/base/views.py

@@ -178,7 +178,9 @@ class ObservationListView(ListView):
         """
         context = super(ObservationListView, self).get_context_data(**kwargs)
         context['satellites'] = Satellite.objects.all()
-        context['authors'] = User.objects.all().order_by('first_name', 'last_name', 'username')
+        context['authors'] = User.objects.annotate(obs_count=Count('observations')) \
+                                         .filter(obs_count__gt=0) \
+                                         .order_by('first_name', 'last_name', 'username')
         context['stations'] = Station.objects.all().order_by('id')
         norad_cat_id = self.request.GET.get('norad', None)
         observer = self.request.GET.get('observer', None)