adding error treatment

Author: nmarasoiu

src/main/java/com/spring/jdbctraining/RegisterController.java

@@ -48,6 +48,7 @@ public DeferredResult<ModelAndView> submitregister(@Validated @ModelAttribute("s
  } else {
  studentImpl.saveStudent(student)
  .doOnCompleted(() -> deferredResult.setResult(new ModelAndView("success")))
+ .doOnError(e -> deferredResult.setErrorResult(e))
  .subscribe();
  }
  return deferredResult;