Scheduler:
- Read templates
- Get the next event time
- Create a new event based on the template and calculated time
- print all scheduled events
- event description
- number of invited people
- display the exact event
- print the exact event
- book the event
print all scheduled events
cancel the booked event
inline_keyboard
- init the structure
- schedule future events
- register a user
- invite to the event
- remind about the booked event