Remove obsolete config entry

config/environments/development.rb

@@ -5,7 +5,6 @@ Rails.application.configure do
   # every request. This slows down response time but is perfect for development
   # since you don't have to restart the web server when you make code changes.
   config.cache_classes = Gitlab::Utils.to_boolean(ENV['CACHE_CLASSES'], default: false)
-  config.hosts << "gdk.test"
 
   # Show full error reports and disable caching
   config.active_record.verbose_query_logs  = true