anchor.diff:  <script>
   var json = '<%= list_registrations_event_path %>';
   var registrations = new Bloodhound({
  -    datumTokenizer: Bloodhound.tokenizers.obj.whitespace('email'),
  -    queryTokenizer: function(d) { return [d];},
  +    datumTokenizer: Bloodhound.tokenizers.obj.whitespace('name', 'email'),
  +    queryTokenizer: Bloodhound.tokenizers.whitespace,
       prefetch: '<%= list_registrations_event_path %>'
  +});
   
  -});
  - 
   registrations.initialize();
  - 
  +
   $('#username').typeahead(
       {
           hint:      true,
  
positive.code:             }
          }
      }
  ); 
  </script>
  
negative.code:         <%= form_tag scan_username_event_path(@event), remote: false do %>
            <div class="input-group">
              <div class="input-group">
                <input required type="text" class="form-control typeahead"
                  placeholder="Ugent username" name="username" id="username">
                <span class="input-group-btn">
                  <button class="btn btn-primary" name="button" type="submit">
  