attaching image in summernote editor (ajax)

summernote-upload-image.js

<script>
/**
 * Super simple WYSIWYG editor using Bootstrap.
 * https://github.com/summernote/summernote
 */
$(document).ready(function() {
  
  // init summernote with height: 200px
  $('.summernote').summernote({
    height: 200,
    
    // tell summernote what to do on image upload
    onImageUpload: function(files) {
      
      // init form data and `append` whatever we need to send along.
      // see: https://developer.mozilla.org/en/docs/Web/API/FormData
      var data = new FormData();
      data.append("file", files[0]);
      
      $.ajax({
        data: data,
        type: "POST",
        url: 'process-upload.php', // url to process this ajax request
        cache: false,
        contentType: false,
        processData: false,
        success: function(url) {
          // the server should give the url of the file we uploaded
          // so that we can tell summernote to insert that url to the editor.
          $('.summernote').summernote('editor.insertImage', url);
        }
      });
    }
  });
}); 
</script>

not working on v0.8.9...

where is process-upload.php