Roadmaps page has no scrollbar

Summary

The roadmaps page has no scrollbar for the list of epics.

Steps to reproduce

Open the gitlab-org roadmaps page and there will be no scrollbar (Well there is a blank one on the side of the page which does nothing)

Tested on Firefox and Chromium on Fedora 28

What is the current bug behavior?

Scrollbar shows up blank and doesn't work

What is the expected correct behavior?

Should be able to scroll through the roadmap page.

Relevant logs and/or screenshots

Output of checks

This bug happens on GitLab.com