Update init.rb

I install redmine_git_hosting plugins. It is located on `http://[host-ip]/redmine`, the topmenu of sidekiq will be `http://[host-ip]/sidekiq`. It is wrong. It should be on `http://[host-ip]/redmine/sidekiq`.

Author: ToroLiu

init.rb

@@ -9,5 +9,5 @@
   author_url 'mailto:[email protected]'
   author 'ogom'
 
-  menu :top_menu, :sidekiq, '/sidekiq', :if => Proc.new {User.current.admin}
+  menu :top_menu, :sidekiq, 'sidekiq', :if => Proc.new {User.current.admin}
 end