I'm not sure exactly what's going on, I do believe it is not using bundler, or maybe it's using system ruby.
I was trying r to run the specs and what I've got was a messaging saying the one of my gems was not installed and asking me to run bundle install.
Is there any specific setting that I should be using?
Unmodified, it should work out of the box (assuming you have a Gemfile in your project, it should work.
Please read carefully :help vroom and make sure you did not turn off bundler support via the setting g:vroom_use_bundle_exec