Set Application controller default URL options to ensure all url_for calls are consistent

Closes #1249

CHANGELOG

 Please view this file on the master branch, on stable branches it's out of date.
 v 7.10.0 (unreleased)
+  - Set Application controller default URL options to ensure all url_for calls are consistent (Stan Hu)
   - Allow HTML tags in Markdown input
   - Include missing events and fix save functionality in admin service template settings form (Stan Hu)
   - Fix "Import projects from" button to show the correct instructions (Stan Hu)

app/controllers/application_controller.rb

@@ -178,6 +178,18 @@ class ApplicationController < ActionController::Base
     response.headers["Expires"] = "Fri, 01 Jan 1990 00:00:00 GMT"
   end
+  def default_url_options
+    if !Rails.env.test?
+      port = Gitlab.config.gitlab.port unless Gitlab.config.gitlab_on_standard_port?
+      { host: Gitlab.config.gitlab.host,
+        protocol: Gitlab.config.gitlab.protocol,
+        port: port,
+        script_name: Gitlab.config.gitlab.relative_url_root }
+    else
+      super
+    end
+  end
+
   def default_headers
     headers['X-Frame-Options'] = 'DENY'
     headers['X-XSS-Protection'] = '1; mode=block'