Is there a ready-made calendar for recording training?

Question

PHP

Hello;
Need a calendar (php, mysql) that can do.
Create an event (authorized users).
Setting a limit on the number of participants (for example, only 20 people can sign up).
Participate (not authorized users).
Cancel participation (suddenly ill).
The calendar is needed for the training class. Maybe there are ready-made solutions (complex)?
Thanks in advance.

Answer 1

Isn't it easier to organize this through Google Calendar?
https://www.google.com/calendar/render?hl=ru&pli=1
click CREATE - and further through the form

Answer 2

meetings can be organized on facebook, vkontakte, odnoglazniki, google calendar, outlook.com, depending on who sits where among the students