Fix for 'Cant find gem bundler (>= 0.a) with executable bundle' issue in Travis CI
Fix for 'Cant find gem bundler (>= 0.a) with executable bundle' issue in Travis CI

Force CI to install bundler version specified in Gemfile.lock
https://bundler.io/blog/2019/05/14/solutions-for-cant-find-gem-bundler-with-executable-bundle.html details the issue and a fix for the problem

mavenlink/brainstem