Resolve "Make exam a many to many field on StudentInfo model"

Closes #233 (closed)

core/migrations/0008_auto_20200922_1148.py

+# Generated by Django 2.2.12 on 2020-09-22 11:48
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0007_auto_20200922_1026'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='examinfo',
+            name='exam',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='exam_infos', to='core.ExamType'),
+        ),
+    ]