anchor.diff:        value: <%= @max_servings %>,
         slide: function( event, ui ) {
           $( "#servings" ).val( ui.value );
  -        
  +
           $.ajax({
             method: "GET",
             url: "/recipe/filter",
  
positive.code: 
  <div id="index_recipes" class="row">
    <%= render "print_recipes" %>
  </div>
negative.code:       value: 5,
        slide: function( event, ui ) {
          $( "#difficulty" ).val( ui.value );
  
          $.ajax({
            method: "GET",
            url: "/recipe/filter",
  