Last Updated: April 12, 2018
·
714
· fool-dev

The PGconn, PGresult, and PGError constants are deprecated on Heroku and Rails

Try to the following, edit your Gemfile like below

gem 'pg', '~> 0.20.0'
Or
gem 'pg', '~> 0.11'

Then bundle install and try, it should work

https://stackoverflow.com/a/49150265/4172515