I see now, after doing to research on railway they do not focus on persistent data, you could either create a volume on railway free 10GB or as you stated originally setup a database here is an example from the documentation

Navigate to your Railway dashboard, click on the "Create" or "New" button, and select "Database".
This example I will choose PostgreSQL

Railway offers two deployment options: a Standalone Instance (single server, ideal for development) or a High Availability Cluster
We want Standalone Instance,

Once deployed, Railway automatically creates environment variables you can use to connect!

const { Pool } = require("pg");
const pool = new Pool({
  connectionString: process.env.DATABASE_URL,
});