How to start postgresql server in heroku?

@muriel.schmidt 

To start a PostgreSQL server in Heroku, you can follow these steps:

1. Log in to your Heroku account and navigate to your Heroku dashboard.
2. Click on the "Resources" tab in the dashboard.
3. Under the "Add-ons" section, click on the button that says "Browse Add-ons".
4. In the search bar, type in "Postgres" and select the "Heroku Postgres" add-on.
5. Choose the plan that best suits your needs (e.g. Hobby Dev, Standard, Premium, etc.) and click on the "Submit Order Form" button.
6. Once the add-on is successfully added to your application, navigate back to the dashboard and click on the "Settings" tab.
7. Under the "Config Vars" section, you will see a new environment variable called "DATABASE_URL" that contains the connection URL for your PostgreSQL database. You can use this URL to connect to your database using a client like pgAdmin or through your application.
8. Your PostgreSQL server is now running on Heroku. You can test the connection and start using it for your application.