UPDATED: Finished moving Message-Id field from <Ticket> to <FollowUp> model.

helpdesk/migrations/0013_store_message_id_field_into_followup_model.py

@@ -0,0 +1,24 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.9.1 on 2016-02-16 18:13
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('helpdesk', '0012_add_submitter_email_id_field_to_ticket'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='ticket',
+            name='submitter_email_id',
+        ),
+        migrations.AddField(
+            model_name='followup',
+            name='message_id',
+            field=models.CharField(blank=True, editable=False, help_text="The Message ID of the submitter's email.", max_length=256, null=True, verbose_name='E-Mail ID'),
+        ),
+    ]