Scale my Heroku voila app containing a postgresql database using gunicorn

I have an already Voila app deployed in Heroku. The aap works correctly but do no scale well, so it reaches the RAM limit ver fast. I need to use gunicorn to avoid this issue (around 300 users should be able to use the app).
Once this issue is solved, I could also need to transale a nested dictionary currently maanaged with pickle module to an already set postgrsql in Heroku