Implemented the interface in all responses

refr #132

src/models/responses/ResponseSelfServiceDonation.ts

@@ -1,11 +1,19 @@
 import { IsInt, IsNotEmpty, IsPositive } from 'class-validator';
 import { DistanceDonation } from '../entities/DistanceDonation';
+import { ResponseObjectType } from '../enums/ResponseObjectType';
+import { IResponse } from './IResponse';
 
 /**
  * Defines the runner selfservice donation response.
  * Why? B/C runner's are not allowed to view all information available to admin users.
 */
-export class ResponseSelfServiceDonation {
+export class ResponseSelfServiceDonation implements IResponse {
+    /**
+    * The responseType.
+    * This contains the type of class/entity this response contains.
+    */
+    responseType: ResponseObjectType = ResponseObjectType.SELFSERVICEDONATION;
+
     /**
      * The donation's donor.
      */