Revert "Change "Group#web_url" to return "/groups/twitter" rather than "/twitter"."

This reverts commit c81ff152.

app/models/group.rb

@@ -68,7 +68,7 @@ class Group < Namespace
   end
 
   def web_url
-    Gitlab::Routing.url_helpers.group_canonical_url(self)
+    Gitlab::Routing.url_helpers.group_url(self)
   end
 
   def human_name

config/routes/group.rb

@@ -12,8 +12,7 @@ constraints(GroupUrlConstrainer.new) do
   end
 end
 
-scope constraints: { id: /[a-zA-Z.0-9_\-]+(?<!\.atom)/ } do
-  resources :groups, except: [:show] do
+resources :groups, constraints: { id: /[a-zA-Z.0-9_\-]+(?<!\.atom)/ }  do
   member do
     get :issues
     get :merge_requests
@@ -32,6 +31,4 @@ scope constraints: { id: /[a-zA-Z.0-9_\-]+(?<!\.atom)/ } do
 
     resources :labels, except: [:show], constraints: { id: /\d+/ }
   end
-  end
-  get 'groups/:id' => 'groups#show', as: :group_canonical
 end

spec/models/group_spec.rb

@@ -265,10 +265,4 @@ describe Group, models: true do
 
     members
   end
-
-  describe '#web_url' do
-    it 'returns the canonical URL' do
-      expect(group.web_url).to include("groups/#{group.name}")
-    end
-  end
 end