old_contents: # -*- coding: utf-8 -*-
  from __future__ import unicode_literals
  
  from django.db import models, migrations
  
  
  class Migration(migrations.Migration):
  
      dependencies = [
      ]
  
      operations = [
          migrations.CreateModel(
              name='Payment',
              fields=[
                  ('id', models.AutoField(serialize=False, auto_created=True, verbose_name='ID', primary_key=True)),
                  ('mp_id', models.IntegerField()),
                  ('status', models.CharField(max_length=16)),
                  ('status_detail', models.CharField(max_length=16)),
                  ('created', models.DateTimeField()),
              ],
          ),
          migrations.CreateModel(
              name='Preference',
              fields=[
                  ('id', models.AutoField(serialize=False, auto_created=True, verbose_name='ID', primary_key=True)),
                  ('mp_id', models.CharField(max_length=46)),
                  ('payment_url', models.URLField()),
                  ('sandbox_url', models.URLField()),
                  ('reference', models.TextField(unique=True)),
              ],
          ),
          migrations.AddField(
              model_name='payment',
              name='preference',
              field=models.ForeignKey(to='mp.Preference', related_name='payments'),
          ),
      ]
  
new_contents: # -*- coding: utf-8 -*-
  from __future__ import unicode_literals
  
  from django.db import models, migrations
  
  
  class Migration(migrations.Migration):
  
      dependencies = [
      ]
  
      operations = [
          migrations.CreateModel(
              name='Notification',
              fields=[
                  ('id', models.AutoField(serialize=False, auto_created=True, primary_key=True, verbose_name='ID')),
                  ('topic', models.CharField(max_length=1, choices=[('o', 'Merchant Order'), ('p', 'Payment')])),
                  ('resource_id', models.CharField(max_length=46)),
                  ('processed', models.BooleanField(default=False)),
                  ('last_update', models.DateTimeField(auto_now=True)),
              ],
          ),
          migrations.CreateModel(
              name='Payment',
              fields=[
                  ('id', models.AutoField(serialize=False, auto_created=True, primary_key=True, verbose_name='ID')),
                  ('mp_id', models.IntegerField(unique=True)),
                  ('status', models.CharField(max_length=16)),
                  ('status_detail', models.CharField(max_length=16)),
                  ('created', models.DateTimeField()),
                  ('approved', models.DateTimeField()),
              ],
          ),
          migrations.CreateModel(
              name='Preference',
              fields=[
                  ('id', models.AutoField(serialize=False, auto_created=True, primary_key=True, verbose_name='ID')),
                  ('mp_id', models.CharField(max_length=46)),
                  ('payment_url', models.URLField()),
                  ('sandbox_url', models.URLField()),
                  ('reference', models.TextField(unique=True)),
              ],
          ),
          migrations.AddField(
              model_name='payment',
              name='preference',
              field=models.ForeignKey(to='mp.Preference', related_name='payments'),
          ),
          migrations.AlterUniqueTogether(
              name='notification',
              unique_together=set([('topic', 'resource_id')]),
          ),
      ]
  
subject: Update the initial migration