old_contents: from celery import Celery
  from celery.utils.log import get_task_logger
  from os import environ
  from redis import Redis
  
  logger = get_task_logger(__name__)
  
  redis_host = environ.get('OMNOMNOM_REDIS_HOST') or 'localhost'
  redis_port = environ.get('OMNOMNOM_REDIS_PORT') or 6379
  
  cache_interval = environ.get('OMNOMNOM_CACHE_INTERVAL') or 60 * 60
  cache_database = environ.get('OMNOMNOM_CACHE_DATABASE') or 0
  
  celery_database = environ.get('OMNOMNOM_CELERY_DATABASE') or 1
  
  cache = Redis(host=redis_host, port=redis_port, db=cache_database)
  
  app = Celery('backend',
               broker='redis://%s:%s/%s' % (redis_host, redis_port, celery_database),
               include=[
                   'canteens.cafenero',
                   'canteens.personalkantine',
                   'canteens.singh',
                   'canteens.studierendenwerk',
                   'omnomgram.tasks',
                   'stats.tasks'
               ]
               )
  app.conf.timezone = 'Europe/Berlin'
  app.conf.beat_schedule = {
      'update cafenero': {
          'task': 'canteens.cafenero.update_cafenero',
          'schedule': cache_interval
      },
      'update singh': {
          'task': 'canteens.singh.update_singh',
          'schedule': cache_interval
      },
      'update personalkantine': {
          'task': 'canteens.personalkantine.update_personalkantine',
          'schedule': cache_interval
      },
      'update en canteen': {
          'task': 'canteens.personalkantine.update_en_canteen',
          'schedule': cache_interval
      },
      'update studierendenwerk': {
          'task': 'canteens.studierendenwerk.update_all_studierendenwerk_canteens',
          'schedule': cache_interval
      }
  }
  
  
  if __name__ == '__main__':
      app.start()
  
new_contents: from celery import Celery
  from celery.utils.log import get_task_logger
  from os import environ
  from redis import Redis
  
  logger = get_task_logger(__name__)
  
  redis_host = environ.get('OMNOMNOM_REDIS_HOST') or 'localhost'
  redis_port = environ.get('OMNOMNOM_REDIS_PORT') or 6379
  
  cache_interval = environ.get('OMNOMNOM_CACHE_INTERVAL') or 60 * 60
  cache_database = environ.get('OMNOMNOM_CACHE_DATABASE') or 0
  
  celery_database = environ.get('OMNOMNOM_CELERY_DATABASE') or 1
  
  cache = Redis(host=redis_host, port=redis_port, db=cache_database)
  cache_date_format = '%Y-%m-%d'
  
  app = Celery('backend',
               broker='redis://%s:%s/%s' % (redis_host, redis_port, celery_database),
               include=[
                   'canteens.cafenero',
                   'canteens.personalkantine',
                   'canteens.singh',
                   'canteens.studierendenwerk',
                   'omnomgram.tasks',
                   'stats.tasks'
               ]
               )
  app.conf.timezone = 'Europe/Berlin'
  app.conf.beat_schedule = {
      'update cafenero': {
          'task': 'canteens.cafenero.update_cafenero',
          'schedule': cache_interval
      },
      'update singh': {
          'task': 'canteens.singh.update_singh',
          'schedule': cache_interval
      },
      'update personalkantine': {
          'task': 'canteens.personalkantine.update_personalkantine',
          'schedule': cache_interval
      },
      'update en canteen': {
          'task': 'canteens.personalkantine.update_en_canteen',
          'schedule': cache_interval
      },
      'update studierendenwerk': {
          'task': 'canteens.studierendenwerk.update_all_studierendenwerk_canteens',
          'schedule': cache_interval
      }
  }
  
  
  if __name__ == '__main__':
      app.start()
  
subject: define cache_date_format in backend