Implemented the interface in all responses

refr #132

src/models/responses/ResponseEmpty.ts

@@ -1,9 +1,17 @@
 import { IsString } from 'class-validator';
+import { ResponseObjectType } from '../enums/ResponseObjectType';
+import { IResponse } from './IResponse';
 
 /**
  * Defines a empty response object.
 */
-export class ResponseEmpty {
+export class ResponseEmpty implements IResponse {
+    /**
+    * The responseType.
+    * This contains the type of class/entity this response contains.
+    */
+    responseType: ResponseObjectType = ResponseObjectType.EMPTY;
+
     @IsString()
     response: string = "nothing here"
 }