development:
  adapter: postgresql
  host: localhost
  database: testtb
  username: app_user
  password: ENV['APP_USER_POSTGRES_PASSWORD']     <= Troublesome line

PGError FATAL:  password authentication failed for user "app_user"

password: <%= ENV['APP_USER_POSTGRES_PASSWORD'] %>

spring stop

puts ActiveRecord::Base.configurations

ap ActiveRecord::Base.configurations

bin/rails runner 'puts ActiveRecord::Base.configurations'