Error while deploying angular app on Heroku server - node.js

Question

I am trying to deploy angular app on Heroku server with the following method.
https://medium.com/#hellotunmbi/how-to-deploy-angular-application-to-heroku-1d56e09c5147
If any one have idea about this, please help me as I am trying to go to root of this error. Thanks in Advance
I changed to -prod to --prod and that helped me to deploy the app successfully, however, while opening the app it gives me "" not found error "" and console error is Failed to load resource: the server responded with a status of 404 (Not Found).
here is the link for the app
https://recipebook-angularapp.herokuapp.com/
This app works perfectly on my local server.
Here is my package.json
{
"name": "recipe-book",
"version": "0.0.0",
"scripts": {
"ng": "ng",
"start": "node server.js",
"build": "ng build",
"test": "ng test",
"lint": "ng lint",
"e2e": "ng e2e",
"postinstall": "ng build --aot -prod"
},
"private": true,
"dependencies": {
"#angular/animations": "~7.2.0",
"#angular/cli": "~7.2.2",
"#angular/common": "~7.2.0",
"#angular/compiler": "~7.2.0",
"#angular/compiler-cli": "~7.2.0",
"#angular/core": "~7.2.0",
"#angular/forms": "~7.2.0",
"#angular/platform-browser": "~7.2.0",
"#angular/platform-browser-dynamic": "~7.2.0",
"#angular/router": "~7.2.0",
"bootstrap": "^3.4.0",
"core-js": "^2.5.4",
"express": "^4.16.4",
"path": "^0.12.7",
"rxjs": "~6.3.3",
"tslib": "^1.9.0",
"typescript": "~3.2.2",
"zone.js": "~0.8.26"
},
"devDependencies": {
"#angular-devkit/build-angular": "~0.12.0",
"#angular/cli": "~7.2.2",
"#angular/compiler-cli": "~7.2.0",
"#angular/language-service": "~7.2.0",
"#types/jasmine": "~2.8.8",
"#types/jasminewd2": "~2.0.3",
"#types/node": "~8.9.4",
"codelyzer": "~4.5.0",
"enhanced-resolve": "^3.3.0",
"jasmine-core": "~2.99.1",
"jasmine-spec-reporter": "~4.2.1",
"karma": "~3.1.1",
"karma-chrome-launcher": "~2.2.0",
"karma-coverage-istanbul-reporter": "~2.0.1",
"karma-jasmine": "~1.1.2",
"karma-jasmine-html-reporter": "^0.2.2",
"protractor": "~5.4.0",
"ts-node": "~7.0.0",
"tslint": "~5.11.0",
"typescript": "~3.2.2"
},
"engines": {
"node": "11.6.0",
"npm": "6.5.0"
}
}
And server.js
//Install express server
const express = require('express');
const path = require('path');
const app = express();
// Serve only the static files form the dist directory
app.use(express.static('./dist/recipe-book'));
app.get('/*', function(req,res) {
res.sendFile(path.join(__dirname,'/dist/recipe-book/index.html'));
});
// Start the app by listening on the default Heroku port
app.listen(process.env.PORT || 8080);