Use the rails 4.2 active job

app/assets/javascripts/supplier/app/templates/tables/index.emblem

@@ -25,6 +25,3 @@
     can manage tables
       a.form-action-new.new-table-button{action "newTable"}= t 'table.new_button'
     = qr-codes-link
-    a.table-qr-codes{path qr_codes_suppliers_tables} target="_blank"
-      span.qr-icon
-      = t 'table.print_qr_codes'

app/controllers/contact_forms_controller.rb

@@ -2,7 +2,7 @@ class ContactFormsController < ApplicationController
   def create
     @contact_form = Cmtool::ContactForm.new(contact_form_params)
     if @contact_form.save
-      Notifier.contact_form(@contact_form.id).deliver
+      Notifier.contact_form(@contact_form.id).deliver_later
       redirect_to root_path, notice: t('contact_form.submitted')
     else
       redirect_to go_to_path('contact', locale: I18n.locale), alert: @contact_form.errors.full_messages.join(', ')

app/models/supplier.rb

@@ -185,7 +185,7 @@ class Supplier
   end
 
   def send_creation_notifications
-    SupplierMailer.creation(self).deliver_now
+    SupplierMailer.creation(self).deliver_later
   end
 
   private