Fix and refactor validator annotaion

Author: hirsch88

src/api/services/UserService.ts

@@ -77,7 +77,7 @@ export class UserService {
      * @param {*} data is the json body of the request
      * @returns {Promise<User>}
      */
-    @Validate
+    @Validate()
     public async create( @Request(UserCreateRequest) data: any): Promise<User> {
         // If the request body was valid we will create the user
         const user = await this.userRepo.create(data);
@@ -93,7 +93,7 @@ export class UserService {
      * @param {*} newUser is the json body of the request
      * @returns {Promise<User>}
      */
-    @Validate
+    @Validate()
     public async update(id: number, @Request(UserUpdateRequest) newUser: any): Promise<User> {
         // Find or fail
         const user = await this.findOne(id);

src/console/templates/service.hbs

@@ -39,14 +39,14 @@ export class {{name.capitalize}}Service {
         return {{name.camelCase}};
     }
 
-    @Validate
+    @Validate()
     public async create( @Request({{name.capitalize}}CreateRequest) body: any): Promise<{{name.capitalize}}> {
         // If the request body was valid we will create the {{name.camelCase}}
         const {{name.camelCase}} = await this.{{name.camelCase}}Repo.create(body);
         return {{name.camelCase}};
     }
 
-    @Validate
+    @Validate()
     public async update(id: number, @Request({{name.capitalize}}UpdateRequest) body: any): Promise<{{name.capitalize}}> {
         // Find or fail
         const {{name.camelCase}} = await this.findOne(id);

src/core/api/Validate.ts

@@ -40,7 +40,7 @@ export const Request = (request: typeof RequestBody) => (target: object, propert
  * @param propertyName
  * @param descriptor
  */
-export const Validate = (target: any, propertyName: string, descriptor: TypedPropertyDescriptor<() => void>): any => {
+export const Validate = () => (target: any, propertyName: string, descriptor: TypedPropertyDescriptor<any>): any => {
     const method = descriptor.value;
     descriptor.value = async function(...args: any[]): Promise<any> {
         const requestParameters: RequestParameter[] = Reflect.getOwnMetadata(requestMetadataKey, target, propertyName);