Some Flask and Flask-related tutorials

1. http://www.compjour.org/lessons/flask-single-page/hello-tiny-flask-app/
2. https://blog.miguelgrinberg.com/post/the-flask-mega-tutorial-part-i-hello-world
3. https://media.readthedocs.org/pdf/flask/latest/flask.pdf
   
4. https://realpython.com/primer-on-jinja-templating/