Setup for User() model not defined

[Abhimanyu Gupta]

/home/nimoy/Documents/nimoy/nimoy-chat
Unhandled exception in thread started by <function check_errors.<locals>.wrapper at 0x7ffb908f71e0>
Traceback (most recent call last):
  File "/home/nimoy/Documents/nimoy/venv/lib/python3.5/site-packages/django/utils/autoreload.py", line 226, in wrapper
    fn(*args, **kwargs)
  File "/home/nimoy/Documents/nimoy/venv/lib/python3.5/site-packages/django/core/management/commands/runserver.py", line 109, in inner_run
    autoreload.raise_last_exception()
  File "/home/nimoy/Documents/nimoy/venv/lib/python3.5/site-packages/django/utils/autoreload.py", line 249, in raise_last_exception
    six.reraise(*_exception)
  File "/home/nimoy/Documents/nimoy/venv/lib/python3.5/site-packages/django/utils/six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "/home/nimoy/Documents/nimoy/venv/lib/python3.5/site-packages/django/utils/autoreload.py", line 226, in wrapper
    fn(*args, **kwargs)
  File "/home/nimoy/Documents/nimoy/venv/lib/python3.5/site-packages/django/__init__.py", line 18, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/home/nimoy/Documents/nimoy/venv/lib/python3.5/site-packages/django/apps/registry.py", line 108, in populate
    app_config.import_models(all_models)
  File "/home/nimoy/Documents/nimoy/venv/lib/python3.5/site-packages/django/apps/config.py", line 202, in import_models
    self.models_module = import_module(models_module_name)
  File "/home/nimoy/Documents/nimoy/venv/lib/python3.5/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 986, in _gcd_import
  File "<frozen importlib._bootstrap>", line 969, in _find_and_load
  File "<frozen importlib._bootstrap>", line 958, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 673, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 673, in exec_module
  File "<frozen importlib._bootstrap>", line 222, in _call_with_frames_removed
  File "/home/nimoy/Documents/nimoy/nimoy-chat/django-permission-backend-nonrel/permission_backend_nonrel/models.py", line 7, in <module>
    **User = get_user_model()**
  File "/home/nimoy/Documents/nimoy/venv/lib/python3.5/site-packages/django/contrib/auth/__init__.py", line 150, in get_user_model
    return django_apps.get_model(settings.AUTH_USER_MODEL)
  File "/home/nimoy/Documents/nimoy/venv/lib/python3.5/site-packages/django/apps/registry.py", line 194, in get_model
    self.check_models_ready()
  File "/home/nimoy/Documents/nimoy/venv/lib/python3.5/site-packages/django/apps/registry.py", line 131, in check_models_ready
    raise AppRegistryNotReady("Models aren't loaded yet.")
django.core.exceptions.AppRegistryNotReady: Models aren't loaded yet.