Error pushing Ruby on Rails to heroku

Question

I have added the pg and rails_12factor gem to my gemfile and tried to push my app to heroku but the website just says application error, I was able to do this successfully a few

Answer 1

You must specify a specific pg version in your gemfile. If not, you will be using the latest available version (1.0.0). But this version is still not supported by Rails. Check here: https://github.com/rails/rails/issues/31673

Yous should use version 0.21

gem 'pg', '0.21'