Now it's the time to add authentication to our website.

We will use the built-in Flask client-side encrypted sessions feature, for which will need to take the following steps to enable:

• Import the session field from Flask;
• Configure a secret encryption key for the session cookies:

  # insert after initializing `app`
  app.config["SECRET_KEY"] = "<type some secret here>"

• Write the Flask functions for login.html and logout.html with the appropriate checks / actions.
• Use the authenticated variable inside the Jinja template and conditionally display the user's status.