UserController annotated as @RestController (#1)

First PR

Reviewed-on: michal.filipczak/DemoApplication#1
Co-authored-by: michal.filipczak2 <michumgw@gmail.com>
Co-committed-by: michal.filipczak2 <michumgw@gmail.com>

Readme.txt

@@ -1,2 +1 @@
 This is documentation of the project
-Changes made on branch "new_feature"

src/main/java/controller/UserController.java

@@ -1,4 +1,5 @@
 package controller;
 
+@RestController
 public class UserController {
 }