old_contents: import csv
  from optparse import make_option
  
  from django.core.management import BaseCommand
  
  from back2back.models import Entry
  
  
  class Command(BaseCommand):
      option_list = BaseCommand.option_list + (
          make_option(
              '-i', '--input',
              action='store',
              dest='input_file',
              default=None,
          ),
          make_option(
              '--reset',
              action='store_true',
              dest='reset',
              default=False,
          ),
      )
  
      def handle(self, *args, **options):
          if options['reset']:
              Entry.objects.all().delete()
          input_file = options['input_file']
          with open(input_file) as f:
              reader = csv.reader(f)
              for row in reader:
                  Entry.objects.create(category=row[0], name=row[1], first_group_number=row[2])
  
new_contents: import collections
  import csv
  from optparse import make_option
  
  from django.core.management import BaseCommand
  
  from back2back.models import Entry
  
  
  class Command(BaseCommand):
      option_list = BaseCommand.option_list + (
          make_option(
              '-i', '--input',
              action='store',
              dest='input_file',
              default=None,
          ),
          make_option(
              '--reset',
              action='store_true',
              dest='reset',
              default=False,
          ),
      )
  
      def handle(self, *args, **options):
          if options['reset']:
              Entry.objects.all().delete()
          input_file = options['input_file']
          category_group_counts = collections.defaultdict(int)
          with open(input_file) as f:
              reader = csv.reader(f)
              for row in reader:
                  if not row[1].strip():
                      continue
                  Entry.objects.create(
                      category=row[0],
                      name=row[1],
                      first_group_number=row[2],
                      first_group_index=category_group_counts[(row[0], row[2])],
                  )
                  category_group_counts[(row[0], row[2])] += 1
  
subject: Save indexes as well when importing entries.