Added .env variables

app.js

@@ -13,7 +13,7 @@ const cors = require('cors') ;
 
 const app = express() ;
 
-const MONGO_URI = `mongodb+srv://Cantilever:Cantilever@cluster0.dqxva.mongodb.net/myFirstDatabase?retryWrites=true&w=majority`
+const MONGO_URI = `mongodb+srv://${process.env.MONGO_USER}:${process.env.MONGO_PASSWORD}@cluster0.dqxva.mongodb.net/${process.env.MONGO_DEFAULT_DATABASE}?retryWrites=true&w=majority`
 
 app.use(cors()) ;
 app.use(bodyparser.json()) ;
@@ -86,7 +86,7 @@ app.use(adminRoute) ;
 mongoose.connect(MONGO_URI, { useNewUrlParser: true,  useUnifiedTopology: true }).
 then(result => {
     console.log('connected');
-    app.listen(5000) ;
+    app.listen(process.env.PORT || 5000) ;
 })
 .catch(err => {
     console.log(err);

controllers/course.js

@@ -146,4 +146,4 @@ module.exports.getTierCourse = async (req , res , next) => {
             error : "error"
         })
     }
-} 
+}

nodemon.json

@@ -0,0 +1,7 @@
+{
+    "env" : {
+        "MONGO_USER":"Cantilever", 
+        "MONGO_PASSWORD" :"Cantilever" ,
+        "MONGO_DEFAULT_DATABASE" :"myFirstDatabase" 
+    }
+}

package.json

@@ -4,7 +4,8 @@
   "description": "",
   "main": "index.js",
   "scripts": {
-    "start:dev": "nodemon app.js"
+    "start:dev": "nodemon app.js" ,
+    "start" : "node app.js"
   },
   "author": "",
   "license": "ISC",