Add agenda service and submit api

Signed-off-by: Asai Neko <sugar@sne.moe>

service/service_event/service.go

@@ -8,6 +8,7 @@ type EventService interface {
 	ListEvents(*EventListPayload) *EventListResult
 	JoinEvent(*EventJoinPayload) *EventJoinResult
 	AttendanceList(*AttendanceListPayload) *AttendanceListResult
+	GetJoinedEvent(*JoinedEventListPayload) *JoinedEventListResult
 }
 
 type EventServiceImpl struct{}