Notification in telegram

There is a site made on laravel, there are users. It is necessary to implement the sending of notifications to each user of the site in the telegram channel.
Notifications must be sent when an event occurs. For example, someone wrote a personal message to the user on the site - he should receive a notification in the telegram, or someone put a like to the user - he should receive a notification in the telegram
Events 4
The fact that each of the users will have to subscribe to the bot - I understand