Many social websites display an activity stream to their users so that they can track what other users do on the platform. An activity stream is a list of recent activities performed by a user or a group of users. For example, Facebook's News Feed is an activity stream. Sample actions can be user X bookmarked image Y or user X is now following user Y. We will build an activity stream application so that every user can see recent interactions of the users they follow. To do so, we will need a model to save the actions performed by users on the website and a simple way to add actions to the feed.

Create a new application named actions inside your project with the following command:

python manage.py startapp actions

Add the new application to INSTALLED_APPS in the settings.py file of your project to activate the application in your...