Revert "small fix"

This reverts commit c8b441a7.

src/libs/routes/user.js

@@ -55,7 +55,7 @@ userApp.post('/authenticate', (req, res) => {
         if (err) throw err;
 
         if(!user){
-            res.json({success: false, msg: 'Authentication failed. User not found.'});
+            res.send({success: false, msg: 'Authentication failed. User not found.'});
         }
         else {
             user.comparePassword(req.body.password, (err, isMatch) => {