Update documentation: Running on Production

[maen08]

Hi there,
Please add a section in the readme file/documentation which explains on how to run this project on production. In the codebase i see there are env. to be configured when running on production eg. enabling CORS when running on production

Eg. File /server/web/app.go 

func main() {
	client, err := mongo.Connect(context.TODO(), clientOptions())
	if err != nil {
		log.Fatal(err)
	}
	defer client.Disconnect(context.TODO())
	mongoDB := db.NewMongo(client)
	// CORS is enabled only in prod profile
	cors := os.Getenv("profile") == "prod"
	app := web.NewApp(mongoDB, cors)
	err = app.Serve()
	log.Println("Error", err)
}

Thanks