Session Storage Adapter for PostgreSQL

This package implements the SessionStorage interface that works with an instance of PostgreSQL.
Tested using PostgreSQL v15

``js
import {shopifyApp} from '@shopify/shopify-app-express';
import {PostgreSQLSessionStorage} from '@shopify/shopify-app-session-storage-postgresql';

const shopify = shopifyApp({
sessionStorage: new PostgreSQLSessionStorage(
'postgres://username:password@host/database',
),
// ...
});

// OR

const shopify = shopifyApp({
sessionStorage: new PostgreSQLSessionStorage(
new URL('postgres://username:password@host/database'),
),
// ...
});

// OR

const shopify = shopifyApp({
sessionStorage: PostgreSQLSessionStorage.withCredentials(
'host.com',
'thedatabase',
'username',
'password',
),
// ...
});
`

If you prefer to use your own implementation of a session storage mechanism that is compatible with the @shopify/shopify-app-express` package, see the implementing session storage guide.