heroku: Gemfile.lock is required issue

Few things

1. Did you placed Gemfile.lock in git? if yes, is it lock (means updated? - you did several times just double check)
2. Just do bundle install on your local prompt.
3. now place Gemfile.lock
   • git add . or you can add only Gemfile.lock with this git add Gemfile.lock
   • git commit -m "commit message here"
   • git push

Now do git push heroku it should work.

Most likely your Gemfile.lock is not committed to your repository. Use git st and ensure that the Gemfile.lock is committed; check your .gitignore file to make sure that you're not accidentally ignoring it.

On your development machine run rm -rf .bundle && bundle install && git add Gemfile.lock && git commit -m "Added Gemfile.lock" Then deploy.