Creating a RESTful API using Flask?
Short answer:
restful.Resource is from a Flask-Restful extension, which is not Flask itself. Miguel's tutorial uses Flask to write a restful interface.
Long answer:
First of all, along with Flask, there are a number of Flask extensions. Although they work together, they are separate packages and are written by individual authors. Flask-Restful is an extension to Flask.
Miguel's tutorial explains how you can make a restful api using Flask by itself.
Flask-Restful with the aim to saving some of us from re-inventing the wheel, promises to turn a custom class(or a custom Python data structure) to a restful web service. Flask-RESTX, a fork of Flask-Restful, auto-generates api documentation with swagger UI.
In addition, Flask also documented the usage of MethodView to allow developers to write their own restful APIs. In parallel, Flask-Restless promises to turn a SqlAlchemy class into a restful web service.
An update(18/07/2016), flask-api turns a function/view into a restful interface and is designed by Tom Christie, the author of django restful framework.
an update(17/03/2021), Flask-RESTPlus does smiliar things as above libraries but it also helps you construct swagger API documentation, which is an extra bonus.
There are many roads to Roma.