add type IEntityWithId to implement unified search function later

src/repository.ts

@@ -1,8 +1,11 @@
 // If types match closely, we can use TypeScript "casting"
 // to convert from data repo to GraphQL schema
 
-export interface ISystem {
+export interface IEntityWithId {
   id: string;
+}
+
+export interface ISystem extends IEntityWithId {
   name: string;
 }
 
@@ -11,24 +14,21 @@ export interface ICoordinates {
   longitude: number;
 }
 
-export interface IRoute {
+export interface IRoute extends IEntityWithId {
-  id: string;
   name: string;
   color: string;
   polylineCoordinates: ICoordinates[];
   systemId: string;
 }
 
-export interface IStop {
+export interface IStop extends IEntityWithId {
-  id: string;
   name: string;
   systemId: string;
   coordinates: ICoordinates;
 }
 
-export interface IShuttle {
+export interface IShuttle extends IEntityWithId {
   coordinates: ICoordinates;
-  id: string;
   name: string;
   routeId: string;
   systemId: string;