How to use the django.db.migrations function in Django

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.db import models, migrations


class Migration(migrations.Migration):

    dependencies = [
    ]

    operations = [
        migrations.CreateModel(
            name='MMCEmail',
            fields=[
                ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
                ('created', models.DateField(auto_now=True)),
                ('email', models.EmailField(help_text=b'Email will be used for send all exceptions from command.', max_length=75)),
                ('is_active', models.BooleanField(default=True, help_text=b'Email may be switched off for a little while.')),
            ],
            options={
                'verbose_name': 'Email',
                'verbose_name_plural': 'Emails',
            },
            bases=(models.Model,),
        ),
        migrations.CreateModel(
            name='MMCHost',
            fields=[

from django.db import migrations, models


class Migration(migrations.Migration):

    dependencies = [
        ('assopy', '0003_add_exrate_fields_to_invoice_model'),
    ]

    operations = [
        migrations.AddField(
            model_name='order',
            name='payment_date',
            field=models.DateTimeField(help_text=b'Auto filled by the payments backend', null=True, blank=True),
        ),

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.db import migrations, models
import djbetty.fields


class Migration(migrations.Migration):

    dependencies = [
    ]

    operations = [
        migrations.CreateModel(
            name='Notification',
            fields=[
                ('id', models.AutoField(verbose_name='ID', primary_key=True, auto_created=True, serialize=False)),
                ('internal_title', models.CharField(max_length=512)),
                ('created_on', models.DateTimeField(auto_now_add=True)),
                ('headline', models.CharField(max_length=512)),
                ('is_published', models.BooleanField(default=False)),
                ('body', models.TextField(blank=True, null=True)),
                ('image', djbetty.fields.ImageField(blank=True, default=None, null=True)),
                ('clickthrough_url', models.URLField(blank=True, null=True)),
                ('clickthrough_cta', models.CharField(blank=True, max_length=30, null=True)),
            ],
            options={
                'abstract': False,
            },

# Generated by Django 2.0.6 on 2018-07-23 15:32

from django.conf import settings
from django.db import migrations, models
import django.db.models.deletion


class Migration(migrations.Migration):

    initial = True

    dependencies = [
        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
    ]

    operations = [
        migrations.CreateModel(
            name='Follow',
            fields=[
                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
                ('follower', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='follower', to=settings.AUTH_USER_MODEL)),
                ('following', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='following', to=settings.AUTH_USER_MODEL)),
            ],
        ),
        migrations.CreateModel(
            name='Skill',
            fields=[
                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
                ('skill_name', models.CharField(blank=True, default='', max_length=100)),

# -*- coding: utf-8 -*-
# Generated by Django 1.10.5 on 2017-02-11 15:30
from __future__ import unicode_literals

from django.db import migrations, models


class Migration(migrations.Migration):

    dependencies = [
        ('accounts', '0025_auto_20170211_1609'),
    ]

    operations = [
        migrations.AddField(
            model_name='profile',
            name='special_chars',
            field=models.CharField(blank=True, default='', help_text='You can specify additional special characters to be shown in the visual keyboard while translating. It can be useful for chars you use frequently but are hard to type on your keyboard.', max_length=30, verbose_name='Special characters'),
        ),

from django.db import models, migrations


def remove_job_submit_sidebar_box(apps, schema_editor):
    """
    Remove jobs-submitajob box
    """
    Box = apps.get_model('boxes', 'Box')
    try:
        submit_box = Box.objects.get(label='jobs-submitajob')
        submit_box.delete()
    except Box.DoesNotExist:
        pass


class Migration(migrations.Migration):

    dependencies = [
        ('jobs', '0002_auto_20150211_1634'),
        ('boxes', '0001_initial'),
    ]

    operations = [
        migrations.RunPython(remove_job_submit_sidebar_box),
    ]

cpus = max(self.cpus_required, 0.25)
    resources.add(NodeResources([Cpus(cpus)]))
    return resources

def get_secrets_key(self):
    """Returns the reference key for job type secrets stored in the secrets backend.

    :returns: The job_type name and version concatenated
    :rtype: str
    """

    return '-'.join([self.name, self.version]).replace('.', '_')



class Migration(migrations.Migration):

    dependencies = [
        ('job', '0029_auto_20170707_1034'),
        ('product', '0010_auto_20170727_1349'),
        ('storage', '0008_auto_20170609_1443'),
        ('queue', '0014_queue'),
    ]

    def populate_queue(apps, schema_editor):
        from job.configuration.json.execution.exe_config import ExecutionConfiguration

        # Go through all of the queued job models and re-populate the queue table
        when_queued = now()
        Job = apps.get_model('job', 'Job')
        JobType = apps.get_model('job', 'JobType')
        JobExecution = apps.get_model('job', 'JobExecution')

# -*- coding: utf-8 -*-
# Generated by Django 1.11.1 on 2017-08-03 20:14
from __future__ import unicode_literals

from django.db import migrations, models


class Migration(migrations.Migration):

    dependencies = [
        ('osf', '0046_merge_20170803_1147'),
    ]

    operations = [
        migrations.AddField(
            model_name='maintenancestate',
            name='level',
            field=models.IntegerField(choices=[(1, b'info'), (2, b'warning'), (3, b'danger')], default=1),
        ),
        migrations.AddField(
            model_name='maintenancestate',
            name='message',
            field=models.TextField(blank=True),
        ),

from django.db import migrations, models
import django.db.models.deletion


class Migration(migrations.Migration):

    initial = True

    dependencies = [
        ('university', '0001_initial'),
        ('partners', '0001_initial'),
    ]

    operations = [
        migrations.AddField(
            model_name='campuspartner',
            name='college_name',
            field=models.ForeignKey(null=True, on_delete=django.db.models.deletion.SET_NULL, to='university.College'),
        ),
        migrations.AddField(
            model_name='campuspartner',
            name='department',
            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, to='university.Department'),
        ),
        migrations.AddField(
            model_name='campuspartner',
            name='education_system',
            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, to='university.EducationSystem'),
        ),
        migrations.AddField(
            model_name='campuspartner',