How to connect postgresql to telegram bot (Heroku)?

Question

PostgreSQL

I have a fully working code for a telegram bot. But the problem is that it is written using sqlite3, which makes it impossible to upload the bot to heroku. Maybe I should read the documentation and blah blah blah, but I just don't have time for that, and besides, the project is very small, just a school project. As far as I know, the sqlite3 and postgresql syntax is the same and all I need for a successful deployment is to rewrite the database connection. I looked at a bunch of videos on YouTube and did not find a working version. Can you briefly explain how to do this?