Filter trainees for active approved users

Closes #477

training/models.py

@@ -6,11 +6,18 @@ from django.utils.safestring import mark_safe
 from versioning.versioning import RevisionMixin
 
 
+class TraineeManager(models.Manager):
+    def get_queryset(self):
+        return super().get_queryset().filter(is_active=True, is_approved=True)
+
+
 @reversion.register(for_concrete_model=False, fields=[])
 class Trainee(Profile, RevisionMixin):
     class Meta:
         proxy = True
 
+    objects = TraineeManager()
+
     # FIXME use queryset
     def started_levels(self):
         return [level for level in TrainingLevel.objects.all() if level.percentage_complete(self) > 0 and level.pk not in self.level_qualifications.values_list('level', flat=True)]