changes from v1.3:

Check-in functionality is ready for production, responsiveness and usability of admin application have been highly improved
Added a new spring-boot executable war.

bugfixes

#41 show ticket details on admin page (thanks to @mfirry)
#44 do not use "STRIPE" as payment type for free reservations (thanks to @mfirry)

new features

#18 Check-in application
#24 Reminder e-mail before event
#45 Shrink active category

Additionally, a "send message to all attendees" functionality has been introduced. The administrator can write the template using mustache , with some limitations