Add __str__ to models, remove null=True in CharField and TextField

apps/member/migrations/0004_replace_null_by_blank.py

@@ -0,0 +1,20 @@
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('member', '0003_create_bde_and_kfet'),
+    ]
+
+    operations = [
+        migrations.RunSQL(
+            "UPDATE member_profile SET address = '' WHERE address IS NULL;",
+        ),
+        migrations.RunSQL(
+            "UPDATE member_profile SET ml_events_registration = '' WHERE ml_events_registration IS NULL;",
+        ),
+        migrations.RunSQL(
+            "UPDATE member_profile SET section = '' WHERE section IS NULL;",
+        ),
+    ]