Add two seperate pages in gitlab merge request for reviewing tools.
in Gemfile
gem 'gitlab_reviewable'
in routes.rb
mount GitlabReviewable::Engine, at: "/reviews"
add two new pages
visit /reviews/diffs?m_project_id=XXX&m_merge_request_id=XXX
visit /reviews/discussion?m_project_id=XXX&m_merge_request_id=XXX