Implemented the interface in all responses

refr #132

src/models/responses/ResponseUserGroup.ts

@@ -1,12 +1,20 @@
 import { IsArray, IsNotEmpty, IsOptional, IsString } from "class-validator";
 import { Permission } from '../entities/Permission';
 import { UserGroup } from '../entities/UserGroup';
+import { ResponseObjectType } from '../enums/ResponseObjectType';
+import { IResponse } from './IResponse';
 import { ResponsePrincipal } from './ResponsePrincipal';
 
 /**
  * Defines the userGroup response.
 */
-export class ResponseUserGroup extends ResponsePrincipal {
+export class ResponseUserGroup extends ResponsePrincipal implements IResponse {
+    /**
+    * The responseType.
+    * This contains the type of class/entity this response contains.
+    */
+    responseType: ResponseObjectType = ResponseObjectType.USERGROUP;
+
     /**
      * The userGroup's name.
      */