logout returns a boolean now which indicates that the logout worked out

src/main/java/hhn/labsw/bugageocaching/controller/Controller.java

@@ -122,11 +122,11 @@ public class Controller {
   @CrossOrigin(origins = "http://localhost:8081") // only for dev purpose
   @RequestMapping("api/logout")
   @ResponseBody
-  String logout(String token) {
+  boolean logout(String token) {
 
     User user = userRepository.findByUsername(token.substring(0, token.indexOf("$")));
     user.setToken("abgemeldet");
     userRepository.save(user);
-    return new Gson().toJson(user);
+    return true;
   }
 }