* add is_anonymous helper function and login_required, has_permission decorators
* add docs for `is_anonymous`, `login_required` and `has_permission` functions
* permission can be `enum.Enum` object; cover with tests
* isort fix
* Add docs example and update demo source code
* Fail with debug
* Fix tests
* Update sql scripts
* Update docs
* Add checking for the password
* Update documentation with launch/usage example
* Launch flake8 instead of pep8 and pyflakes