[Django]-What causes "Unknown command: 'mkmigrations'" in Django?

As others have noticed, your Django version should be 1.7; this is caused by your installation of django-addthis.

The current version of django-addthis explicitly states Django<=1.6.5 as a dependency. For some reason, this prompts pip to downgrade your installation:

$ pip install django-addthis
Downloading/unpacking django-addthis
  Downloading django-addthis-2.0.0.tar.gz
  Running setup.py (path:...) egg_info for package django-addthis

Downloading/unpacking Django>=1.4,<=1.6.5 (from django-addthis)
  Downloading Django-1.6.5-py2.py3-none-any.whl (6.7MB): 6.7MB downloaded
Installing collected packages: django-addthis, Django
  Running setup.py install for django-addthis

  Found existing installation: Django 1.7.5
    Uninstalling Django:
      Successfully uninstalled Django
Successfully installed django-addthis Django

The last four lines show what happened when I tried this on one of my own Django 1.7 projects. pip happily downgrades your Django app. And since virtualenv dependencies are usually not stored in Git, you won’t see this when you do a git status.

The only solution is to uninstall django-addthis and reinstall the correct Django version:

$ pip uninstall django-addthis && pip install --upgrade -r requirements.txt