Install missing gem executables with `bundle install`

When: ```bash $ bundle exec cucumber bundler: command not found: cucumber Install missing gem executables with `bundle install` ``` Do: ```bash $ rm .bundle/config # remove a broken bundler configuration $ gem update --system # might help if rubygems is outdated / broken $ gem update bundler # might help if bundler is outdated / broken $ bundle install # dependency hell ``` Or, start using, e.g., golang, crystal, etc.