feat: complete day 9

day9/middleware/Maintenance.js

@@ -0,0 +1,11 @@
+const config = require("../config");
+
+module.exports = function (req, res, next) {
+  if (config.maintenance) {
+    return res.status(503).json({
+      success: false,
+      error: "Service is under maintenance. Please try again later.",
+    });
+  }
+  next();
+};