Before we implement the logic to store notifications in the database, let’s look at the Notifications API.
The Notifications API consists of just two methods: instrument and subscribe. The former is called when we want to instrument and publish an event, and for Action Controller processing, it looks like this:
format: :html, path: "/", action: "index") do
The first argument is the name of the event published, which in this case is process_action.action_controller, and the second is a hash with information about the event, called payload. To subscribe to those ...