【ADD】示例文件，解决空的包提交不了问题

railway-admin/src/main/java/com/railway/web/controller/business/safetool/DemoController.java → railway-admin/src/main/java/com/railway/web/controller/business/safetool/SafeToolDemoController.java

@@ -1,5 +1,5 @@
 package com.railway.web.controller.business.safetool;
 
-public class DemoController {
+public class SafeToolDemoController {
 
 }