In order to configure your environment variables, you should copy the .env.example file under the name .env. You should then fill in this file with your Postgres database connection parameters.

For example, your .env may look something like this:

APP_PORT=3000
DB_HOST=your_host
DB_USER=your_user
DB_PASS=your_password
DB_NAME=your_database

Make sure to replace your_host, your_user, your_password, your_database with your actual Postgres database details.

The application will initialize with a migration that creates the users table and inserts an initial user row.

To update a user's balance, make a POST request to http://localhost:3000/user/update-balance with the following parameters in your request body:

userId The id of the user you wish to update (id of first user should be 1 after migrations passed),

amount The amount to add or subtract from the user's balance,

Below is an example of such request:

fetch('http://localhost:3000/user/update-balance', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    userId: user_id_goes_here,
    amount: integer_amount_goes_here
  }),
});