added get_absolute_url in Event model

widget_princessgabi/widget_calendar/models.py

 from django.db import models
 from assignments.models import Course
+from django.urls import reverse
 
 # Create your models here.
 class Location(models.Model):
@@ -24,3 +25,6 @@ class Event(models.Model):
 
     def __str__(self):
         return self.activity
+    
+    def get_absolute_url(self):
+        return reverse('event-details', kwargs={'pk': self.pk})
\ No newline at end of file