Mongodb – ValidationError: name: Path `name` is required., tech: Path `tech` is required. In mongoose

is anything I’m doing wrong, I get this error Error ValidationError: name: Path name is required., tech: Path tech is required. while POST the data in postman.

here is my index.js

const express = require('express')
const mongoose = require('mongoose')
const mongoDB  = 'mongodb://127.0.0.1:27017/local_library'
const routers = require('../public/app')

const bodyParser = require("body-parser")

const app = express()


app.use(bodyParser.urlencoded({ extended: true }));


app.use('/app', routers)

app.use(bodyParser.json());

mongoose.connect(mongoDB, { useNewUrlParser: true, useUnifiedTopology: true })
const con = mongoose.connection

con.on('open', () => {
    console.log('connected..')

})

app.use(express.json)

app.listen(3000, () => {
    console.log('server started')
})

schema.js

const mongoose = require('mongoose')

const Schema = mongoose.Schema;

const SomeModelSchema  = new Schema({
    name: {
         type: String,
         required: true  
     },
     tech: {
         type: String,
    required: true
 },

})

module.exports = mongoose.model('SomeModel', SomeModelSchema )

app.js

const bodyParser = require('body-parser')
const express = require('express')
const router = express.Router() 
const SomeModel = require('../models/schema.js')

router.get('/', async(req, res) => {
    try{
        const receive = await SomeModel.find()
        res.json(receive)
    }catch(err){
        res.send('Error ' + err)
    }
 })

router.post ('/', async(req, res) => {
    const send = new SomeModel({
           name: req.body.name,
           tech: req.body.tech,

    })

    try{
        const a1 = await send.save()
        res.json(a1)
    
    }catch(err){
        res.send('Error' + err)
    }
})

module.exports = router