Avoid installing Gems in system path
When trying to build the 13.12
image (https://gitlab.com/gitlab-org/gitlab-docs/-/jobs/2012032682), we get a permissions error.
This MR reconfigures Bundler before that runs.
When trying to build the 13.12
image (https://gitlab.com/gitlab-org/gitlab-docs/-/jobs/2012032682), we get a permissions error.
This MR reconfigures Bundler before that runs.