You can "manually" squash migrations, by

1. clear migration history

   python manage.py migrate --fake myapp zero
   

2. Remove the migration files

   rm django/myapp/migrations/*.py
   

3. Make new migration files (there will only be one, this will make the new initial migration file)

   python manage.py makemigrations
   

4. And migrate to it

   python manage.py migrate --fake-initial
   

The reason for --fake and --fake-initial are to prevent the database from being updated during this process.