title: file upload field on checkout page woocommerce
body: <p>I want to add a file upload field on checkout page in woocommerce.I have added it but when I click on "Place order" button and try to check post values,$_FILES array is empty while other fields on the same page ,same form are coming with respective values.I am using response using print_r().This issue also had been asked in below thread and explained well.I have exactly same problem as in this thread.</p>
  
  <p><a href="https://stackoverflow.com/questions/23725015/how-to-upload-a-image-in-woocommerce-checkout-page-and-link-it-to-the-order">How to upload a image in woocommerce checkout page and link it to the order</a></p>
  
  <p>Any help highly appreciated.</p>