Add celery config to the docs

[plumber-craic]

Feature Request

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Is your feature request related to a problem?

Request to add some info to the docs

Describe the solution you'd like

A section for django-celery-beat periodic tasks

Additional context

Since the docs mention that additional integration examples would be welcome, and I don't know how to make a proper PR:

django-celery-beat

myapp/management/my_custom_command.py (can be called on app startup)

from django.core.management.base import BaseCommand, CommandError
from django_celery_beat.models import CrontabSchedule, PeriodicTask
import pytz


class Command(BaseCommand):
    help = 'Creates crontab schedule objects and periodic tasks that use them'

    def handle(self, *args, **options):
        every_day, _ = CrontabSchedule.objects.get_or_create(
            minute='0',
            hour='0',
            day_of_week='*',
            day_of_month='*',
            month_of_year='*',
            timezone=pytz.timezone('UTC')
        )

        PeriodicTask.objects.get_or_create(
            crontab=every_day,
            name='Backup DB',
            task='myapp.tasks.backup_db',
        )

        PeriodicTask.objects.get_or_create(
            crontab=every_day,
            name='Backup Media',
            task='myapp.tasks.backup_media',
        )

tasks.py

from celery import Celery
from django.core import management

app = Celery()


@app.task
def backup_db():
    management.call_command('dbbackup')


@app.task
def backup_media():
    management.call_command('mediabackup')

PR link

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