Add short path route for groups.

config/routes.rb

@@ -327,5 +327,7 @@ Gitlab::Application.routes.draw do
     end
   end
 
+  get ':id' => "groups#show", constraints: {id: /(?:[^.]|\.(?!atom$))+/, format: /atom/}
+
   root to: "dashboard#show"
 end

spec/routing/routing_spec.rb

@@ -238,3 +238,15 @@ end
 describe "Authentication", "routing" do
   # pending
 end
+
+describe "Groups", "routing" do
+  it "to #show" do
+    get("/groups/1").should route_to('groups#show', id: '1')
+  end
+
+  it "redirect" do
+    # get("/groups/1").should redirect_to("/groups/1")
+    get("/1").should route_to('groups#show', id: '1')
+  end
+end
+