diff --git a/server/routers/kfu-m-24-1/eng-it-lean/units/index.js b/server/routers/kfu-m-24-1/eng-it-lean/units/index.js
index 284556a..d672dcd 100644
--- a/server/routers/kfu-m-24-1/eng-it-lean/units/index.js
+++ b/server/routers/kfu-m-24-1/eng-it-lean/units/index.js
@@ -5,15 +5,16 @@ const router = require('express').Router();
 module.exports = router;
 
 const data = require('./units.json');
-const users = require('../users/users.json');
 router.get('/', (req, res) => {
   // for every data set author from users and save it to authoredData variable
+  const users = require('../users/users.json');
   const authoredData = data.map((unit) => {
     const user = users.find((user) => user.public_id == unit.author);
+    let authoredUnit = undefined;
     if (user) {
-      unit.author = user;
+      authoredUnit = { ...unit, author: user };
     }
-    return unit;
+    return authoredUnit;
   });
 
   res.send(authoredData);
@@ -39,9 +40,8 @@ router.post('/:id', (req, res) => {
 
   data.splice(index, 1);
 
-  data.push(updatedUnit);
+  data.push({...updatedUnit, author: updatedUnit.author.public_id});
 
-  fs.writeFileSync(path.join(__dirname, 'units.json'), JSON.stringify(data));
   res.status(200).send(data); 
 });
 
@@ -61,12 +61,8 @@ router.put('/', (req, res) => {
   }
 
   const newId = data.length + 1;
-  // const filename = newUnit.name.replace(/([a-z])([A-Z])/g, '$1-$2').toLowerCase();
-  // fs.writeFileSync(path.join(__dirname, 'data', `${filename}.md`), newUnit.content);
+  data.push({ ...newUnit, id: newId });
 
-  data.push({ ...unit, id: newId });
-
-  fs.writeFileSync(path.join(__dirname, 'units.json'), JSON.stringify(data));
   res.status(200).send(data);
 });
 
@@ -79,11 +75,11 @@ router.delete('/:id', (req, res) => {
   }
 
   data.splice(index, 1);
-  fs.writeFileSync(path.join(__dirname, 'units.json'), JSON.stringify(data));
   res.send({ message: `Unit with ID ${id} deleted` });
 });
 
 router.get('/:id', (req, res) => {
+  const users = require('../users/users.json');
   const id = parseInt(req.params.id);
   const unit = data.find((unit) => unit.id === id);