Wrap group removal into service

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/controllers/admin/groups_controller.rb

@@ -47,7 +47,7 @@ class Admin::GroupsController < Admin::ApplicationController
   end
 
   def destroy
-    @group.destroy
+    DestroyGroupService.new(@group, current_user).execute
 
     redirect_to admin_groups_path, notice: 'Group was successfully deleted.'
   end

app/controllers/groups_controller.rb

@@ -82,7 +82,7 @@ class GroupsController < Groups::ApplicationController
   end
 
   def destroy
-    @group.destroy
+    DestroyGroupService.new(@group, current_user).execute
 
     redirect_to root_path, notice: 'Group was removed.'
   end

app/services/destroy_group_service.rb

+class DestroyGroupService
+  attr_accessor :group, :current_user
+
+  def initialize(group, user)
+    @group, @current_user = group, user
+  end
+
+  def execute
+    @group.destroy
+  end
+end

lib/api/groups.rb

@@ -62,7 +62,7 @@ module API
       delete ":id" do
         group = find_group(params[:id])
         authorize! :admin_group, group
-        group.destroy
+        DestroyGroupService.new(group, current_user).execute
       end
 
       # Transfer a project to the Group namespace