removed taskid from alarm

lib/model/alarm/alarm.dart

@@ -4,7 +4,6 @@ import 'relative_time_alarm.dart';
 
 abstract class Alarm {
   String get id;
-  String get taskId;
   AlarmType get alarmType;
   Map<String, dynamic> toJson();
 
@@ -31,7 +30,7 @@ abstract class Alarm {
   }
 
   @override
-  int get hashCode => taskId.hashCode;
+  int get hashCode => id.hashCode;
 }
 
 enum AlarmType { timeFixed, timeRelative, location }