Error parsing your Gemfile; can't find gem bundler (>= 0.a)

Issue

You are seeing the following errors somewhere in the build logs when trying to build your Rails app.

There was an error parsing your Gemfile, we cannot continue
`find_spec_for_exe': can't find gem bundler (>= 0.a) with executable bundle (Gem::GemNotFoundException)

Resolution

Try running the following commands to correct the version of bundler that is set in your Gemfile.lock file.

gem install bundler -v 2.0.1
bundle update --bundler
git add Gemfile.lock; git commit -m 'update bundler version';