diff --git a/lib/issues_form_hook_listener.rb b/lib/issues_form_hook_listener.rb
index 53373f5..d5056a6 100644
--- a/lib/issues_form_hook_listener.rb
+++ b/lib/issues_form_hook_listener.rb
@@ -13,7 +13,7 @@ class IssuesFormHookListener < Redmine::Hook::ViewListener
   # Load the javascript
   def view_layouts_base_html_head(context = {})
     js = javascript_include_tag 'vehicles.coffee', :plugin => 'redmine_qbo' 
-    js << javascript_include_tag 'update_vehicles.coffee', :plugin => 'redmine_qbo'
+    js += javascript_include_tag 'update_vehicles.coffee', :plugin => 'redmine_qbo'
     return js
   end