feat: add validation for login

server/src/middleware/error.js

@@ -1,5 +1,5 @@
 // eslint-disable-next-line no-unused-vars
 export default function errorHandler(err, req, res, next) {
   console.error(err.stack) // Log error stack trace to the console
-  res.status(500).send({ message: err.message }) // Send error response
+  res.status(500).send({ message: 'Something broke!' }) // Send error response
 }