ImportError: No module named django.core.management

 I got this error when running

python manage.py migrate


Traceback (most recent call last):

  File "manage.py", line 8, in <module>

    from django.core.management import execute_from_command_line

ImportError: No module named django.core.management

And then realised I should have run 

python3 manage.py migrate

Doh!