Use another scope to add the - prefix, feedback:

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11407#note_30922591

config/routes/project.rb

@@ -216,7 +216,8 @@ constraints(ProjectUrlConstrainer.new) do
         end
       end
 
-      resources :jobs, path: '-/jobs', only: [:index, :show], constraints: { id: /\d+/ } do
+      scope '-' do
+        resources :jobs, only: [:index, :show], constraints: { id: /\d+/ } do
           collection do
             post :cancel_all
 
@@ -247,6 +248,7 @@ constraints(ProjectUrlConstrainer.new) do
             post :keep
           end
         end
+      end
 
       Gitlab::Routes::LegacyBuilds.new(self).draw