Attempt a different migration to remove null from text fields

apps/map/migrations/0069_remove_null_from_text_fields.py

@@ -62,7 +62,7 @@ def remove_nulls(apps, schema_editor):
     study = apps.get_model('map', 'CaseStudy')
     for study in CaseStudy.objects.all():
         for field in string_fields:
-            if study._meta.get_field(field) == None:
+            if getattr(study, field) == None:
                 setattr(study, field, '')
 
         study.save()