Doplnit README about pyworking.cz HOT 3 OPEN

[pyworking.cz (master)]$ python3.6 -m venv __venv__ && . __venv__/bin/activate 
(__venv__) [pyworking.cz (master *)]$ pip install .
Processing .../pyvec/pyworking.cz
...
Successfully installed Jinja2-2.10 MarkupSafe-1.0 Werkzeug-0.14.1 click-6.7 flask-0.12.2 itsdangerous-0.24 markdown-2.6.11 markdown-urlize-0.2.0 pyworking-cz-0.0.1 pyyaml-3.12
(__venv__) [pyworking.cz (master *)]$ export FLASK_DEBUG=1
(__venv__) [pyworking.cz (master *)]$ FLASK_APP=pyworking_cz:app flask run
 * Serving Flask app "pyworking_cz:app"
 * Forcing debug mode on
 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 116-940-349
127.0.0.1 - - [16/Feb/2018 16:34:02] "GET / HTTP/1.1" 500 -
Traceback (most recent call last):
  File ".../pyvec/pyworking.cz/__venv__/lib/python3.6/site-packages/flask/app.py", line 1997, in __call__
    return self.wsgi_app(environ, start_response)
  File ".../pyvec/pyworking.cz/__venv__/lib/python3.6/site-packages/flask/app.py", line 1985, in wsgi_app
    response = self.handle_exception(e)
  File ".../pyvec/pyworking.cz/__venv__/lib/python3.6/site-packages/flask/app.py", line 1540, in handle_exception
    reraise(exc_type, exc_value, tb)
  File ".../pyvec/pyworking.cz/__venv__/lib/python3.6/site-packages/flask/_compat.py", line 33, in reraise
    raise value
  File ".../pyvec/pyworking.cz/__venv__/lib/python3.6/site-packages/flask/app.py", line 1982, in wsgi_app
    response = self.full_dispatch_request()
  File ".../pyvec/pyworking.cz/__venv__/lib/python3.6/site-packages/flask/app.py", line 1614, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File ".../pyvec/pyworking.cz/__venv__/lib/python3.6/site-packages/flask/app.py", line 1517, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File ".../pyvec/pyworking.cz/__venv__/lib/python3.6/site-packages/flask/_compat.py", line 33, in reraise
    raise value
  File ".../pyvec/pyworking.cz/__venv__/lib/python3.6/site-packages/flask/app.py", line 1612, in full_dispatch_request
    rv = self.dispatch_request()
  File ".../pyvec/pyworking.cz/__venv__/lib/python3.6/site-packages/flask/app.py", line 1598, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File ".../pyvec/pyworking.cz/__venv__/lib/python3.6/site-packages/pyworking_cz/views.py", line 12, in index
    events = load_events()
  File ".../pyvec/pyworking.cz/__venv__/lib/python3.6/site-packages/pyworking_cz/model.py", line 33, in load_events
    event_dir = get_data_dir() / 'events'
  File ".../pyvec/pyworking.cz/__venv__/lib/python3.6/site-packages/pyworking_cz/model.py", line 25, in get_data_dir
    raise Exception('Data directory is not a directory: {}'.format(data_dir))
Exception: Data directory is not a directory: .../pyvec/pyworking.cz/__venv__/lib/python3.6/site-packages/data
...^C
(__venv__) [pyworking.cz (master *)]$ ln -s .../pyvec/pyworking.cz/data/ __venv__/lib/pyon3.6/site-packages/data
(__venv__) [pyworking.cz (master *)]$ FLASK_APP=pyworking_cz:app flask run