mark "booking and scheduling" and "polls and events" sections as related

README.md

@@ -1298,6 +1298,8 @@ _Related: [Monitoring](#monitoring)_
 
 **[`^        back to top        ^`](#)**
 
+_Related: [Booking and Scheduling](#booking-and-scheduling)_
+
 - [Calagator](https://calagator.org/) - Event aggregator. ([Source Code](https://github.com/calagator/calagator)) `MIT` `Ruby`
 - [Clerk](https://github.com/AppMini/Clerk) - Simple event logger to keep track of periodic events, habits, etc. as they occur. `GPL-3.0` `PHP`
 - [Croodle](https://github.com/jelhan/croodle) - Croodle is an end-to-end encrypted web application to schedule a date or to do a poll on any topic. `MIT` `Javascript`
@@ -1318,6 +1320,11 @@ _Related: [Monitoring](#monitoring)_
 
 ### Booking and Scheduling
 
+**[`^        back to top        ^`](#)**
+
+_Related: [Polls and Events](#polls-and-events)_
+
+
 - [Alf.io](https://alf.io/) - The open source ticket reservation system. ([Demo](https://demo.alf.io/authentication), [Source Code](https://github.com/alfio-event/alf.io)) `GPL-3.0` `Java`
 - [Calendso](https://calendso.com/) - The open-source online appointment scheduling system. ([Demo](https://app.calendso.com/bailey), [Source Code](https://github.com/calendso/calendso)) `MIT` `Nodejs`
 - [Easy!Appointments](https://easyappointments.org/) - A highly customizable web application that allows your customers to book appointments with you via the web. ([Demo](https://easyappointments.org/demo/), [Source Code](https://github.com/alextselegidis/easyappointments)) `GPL-3.0` `PHP`