Doesn't start as expected in the documentation

[burhan]

Followed the documentation; created a new virtual environment and then install galley; and then the following:

$ galley
usage: galley [-h] [--no-destroy] [config] [pattern]
galley: error: argument config: can't open '/Users/burhan/work/projects/django/docs/.galley.yml': [Errno 2] No such file or directory: '/Users/burhan/work/projects/django/docs/.galley.yml'

So what's this .galley.yml?