fix test class name

src/main/java/istvan/java/controllers/TestController.java

@@ -4,7 +4,7 @@ import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RestController;
 
 @RestController
-public class test {
+public class TestController {
 
     @GetMapping("hello")
     public String hello(){