Where should i put a-certificate.crt file?

I had trouble connecting to digitalocean database in node js and was getting errors such as:

Error: self signed certificate in certificate chain.

or

error: no pg_hba.conf entry for host "x.x.x.x", user "------", database "------", SSL off

but then I added ca-certificate.crt file into my node.js app newly created ssl folder and wrote this

const pg = require('pg')
const fs = require('fs')

const pool = new pg.Pool({
    user: "-----",
    password: "--------",
    host: "-----------",
    port: 25060,
    database: "----",
    ssl: true,
    ssl: {
      ca: fs.readFileSync('../ssl/ca-certificate.crt'),
      rejectUnauthorized: true,
    }

module.exports = pool;

This line fixed all those errors and now I can connect to the database

ca: fs.readFileSync('../ssl/ca-certificate.crt'),

but I feel it’s not very common practice to have ca-certificate.crt file in my app folder so I would like to know how to handle this?