Fix student import test on PostgreSQL

stages/migrations/0005_extend_student_avs.py

@@ -0,0 +1,16 @@
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stages', '0004_add_student_report_fields'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='student',
+            name='avs',
+            field=models.CharField(blank=True, max_length=20, verbose_name='No AVS'),
+        ),
+    ]