添加了Swagger API文档以及诸多优化

main.go

@@ -1,3 +1,14 @@
+// DNS Server API
+// @title DNS Server API
+// @version 1.0
+// @description DNS服务器API文档
+// @termsOfService http://swagger.io/terms/
+// @contact.name API Support
+// @contact.email support@example.com
+// @license.name Apache 2.0
+// @license.url http://www.apache.org/licenses/LICENSE-2.0.html
+// @host localhost:8080
+// @BasePath /api
 package main
 
 import (