fix mongdb name;

server.js

@@ -6,7 +6,7 @@ const mongoose = require('mongoose')
 require('dotenv').config()
 const app = express()
 const PORT = process.env.PORT
-const MONGODB_URI = process.env.MONGODB_URI + '/merncrud'
+const MONGODB_URI = process.env.MONGODB_URI
 
 // middleware
 app.use(express.json()) // use .json(), not .urlencoded()