Fixed #58, introduced last sign-up date. The reminders will be set seven and one days before this date.
(cherry picked from commit fb803eb)
Fixed +/- bug
(cherry picked from commit 1acc02a)
Added date range validation for last sign-up date
(cherry picked from commit e09737a)
Fixed #57, Event description max length is now 10k characters
(cherry picked from commit 899d85f)