Merge branch 'dz-allow-nested-group-routing' into 'master'

Add nested groups support to the routing

## What does this MR do?

It allows routing with `/` in namespace name 

## Why was this MR needed?

For nested groups feature(https://gitlab.com/gitlab-org/gitlab-ce/issues/2772). We need URI like `/group/subgroup/project` be routed correctly


## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- ~~[Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)~~
- ~~API support added~~
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/2772

See merge request !7459

1 files changed, 8 insertions, 0 deletions

diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 2713c0f1dc8..bcc0b17bce2 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -49,6 +49,14 @@ class ApplicationController < ActionController::Base
     render_404
   end
 
+  def route_not_found
+    if current_user
+      not_found
+    else
+      redirect_to new_user_session_path
+    end
+  end
+
   protected
 
   # This filter handles both private tokens and personal access tokens