Current master not installable from source

[PetrDlouhy]

If I run

 pip install git+https://github.com/jazzband/django-categories#egg=django-categories

the pip will not create categories folder with django-categories files in the site-packages directory. If I try to run the application I got following error:

Traceback (most recent call last):
  File "/usr/local/lib/python3.9/threading.py", line 973, in _bootstrap_inner
    self.run()
  File "/usr/local/lib/python3.9/site-packages/sentry_sdk/integrations/threading.py", line 69, in run
    reraise(*_capture_exception())
  File "/usr/local/lib/python3.9/site-packages/sentry_sdk/_compat.py", line 54, in reraise
    raise value
  File "/usr/local/lib/python3.9/site-packages/sentry_sdk/integrations/threading.py", line 67, in run
    return old_run_func(self, *a, **kw)
  File "/usr/local/lib/python3.9/threading.py", line 910, in run
    self._target(*self._args, **self._kwargs)
  File "/usr/local/lib/python3.9/site-packages/django/utils/autoreload.py", line 64, in wrapper
    fn(*args, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/django/core/management/commands/runserver.py", line 115, in inner_run
    autoreload.raise_last_exception()
  File "/usr/local/lib/python3.9/site-packages/django/utils/autoreload.py", line 87, in raise_last_exception
    raise _exception[1]
  File "/usr/local/lib/python3.9/site-packages/django/core/management/__init__.py", line 381, in execute
    autoreload.check_errors(django.setup)()
  File "/usr/local/lib/python3.9/site-packages/django/utils/autoreload.py", line 64, in wrapper
    fn(*args, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/django/__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/usr/local/lib/python3.9/site-packages/django/apps/registry.py", line 91, in populate
    app_config = AppConfig.create(entry)
  File "/usr/local/lib/python3.9/site-packages/django/apps/config.py", line 223, in create
    import_module(entry)
  File "/usr/local/lib/python3.9/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1030, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 984, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'categories'