add cors annontation

backend/secret-archive-rest/src/main/java/cz/fi/muni/pa165/seminar4/group7/controller/CountryController.java

@@ -16,6 +16,8 @@ import java.util.stream.StreamSupport;
 /**
  * @author Juraj Fiala
  */
+// TODO Find more suitable solution for CORS
+@CrossOrigin(origins = "http://localhost:4200")
 @RestController
 @RequestMapping(value = "/countries")
 public class CountryController {