Updated calendar to have CRUD functionality (mostly).

backend/modules/calendar/service.py

@@ -21,6 +21,15 @@ def get_calendar_events(db: Session, user_id: int, start: datetime, end: datetim
         query = query.filter(CalendarEvent.end_time <= end)
     return query.all()
 
+def get_calendar_event_by_id(db: Session, user_id: int, event_id: int):
+    event = db.query(CalendarEvent).filter(
+        CalendarEvent.id == event_id,
+        CalendarEvent.user_id == user_id
+    ).first()
+    if not event:
+        raise not_found_exception()
+    return event
+
 def update_calendar_event(db: Session, user_id: int, event_id: int, event_data):
     event = db.query(CalendarEvent).filter(
         CalendarEvent.id == event_id,