Despite updating the gem sqlite 3 to be under development in gemfile and adding gem pg to production, it is still not working. I tried various ways without completely eliminating sqlite3 and going to postgres1 https://devcenter.heroku.com/articles/sqlite3, but no avail.
Several hours of hair tearing, teeth clenching later, I found my angel solution. Delete gemfile.lock and run bundle install again. Steps below:
- remove Gemfile.Lock.
- run bundle install –without production
- git add .
- git commit -am “bundle update with sqlite under development and test”
- git push heroku master
And the world is right again!