Resolve "update for feedbackmodel"

Closes #89 (closed)

core/migrations/0003_auto_20180207_1922.py

+# Generated by Django 2.0.2 on 2018-02-07 19:22
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0002_auto_20180202_1421'),
+    ]
+
+    operations = [
+        migrations.RenameField(
+            model_name='feedbackcomment',
+            old_name='is_final',
+            new_name='visible_to_student',
+        ),
+    ]