+ # The 'gem install bundler line below' is cf.
+ # https://bundler.io/blog/2019/05/14/solutions-for-cant-find-gem-bundler-with-executable-bundle.html,
+ # until we get bundler 2.7.10/3.0.0 or higher
+ gem install bundler --no-document -v "$(grep -A 1 "BUNDLED WITH" Gemfile.lock | tail -n 1|tr -d ' ')"