I had a fully-functional website hosted in Heroku (the code is Ruby-in-Rails and the database is PostgreSQL), until I logged in to Heroku as admin to change some add-ons to free plan and incidentally dropped the PostgreSQL add-on.
Now the website is off and I need help to reconfigure the add-ons, restore the database and put the website back online.
No code change is required, as no code was changed since the website was fully functional. We need only to restore the database and reconfigure the add-ons.
Fortunately I have a recent backup of the PostgreSQL database and I managed to successfully restore this backup into a PostgreSQL server in my PC. All the data in the backup seems to be ok.