CE upstream

CE changes https://gitlab.com/gitlab-org/gitlab-ce/compare/d636efbe26ee51030bb108d889c2ef867570358a...0c36b810abede73b3cf59f951e7467dbac54ec98?expand_all_diffs=1

config/routes/group.rb

@@ -3,7 +3,7 @@
 constraints(GroupUrlConstrainer.new) do
   scope(path: ':id',
         as: :group,
-        constraints: { id: /[a-zA-Z.0-9_\-]+(?<!\.atom)/ },
+        constraints: { id: Gitlab::Regex.namespace_route_regex },
         controller: :groups) do
     get '/', action: :show
     patch '/', action: :update