[Django]-How to redo a migration on django 1.8 after using –fake

You should first set your current state to 0003 with --fake (assuming 0003 is the last migration you really have applied):

python manage.py migrate --fake core 0003

And then proceed as usual:

python manage.py migrate core

Relevant documentation: https://docs.djangoproject.com/en/dev/ref/django-admin/#migrate