text: $.each(data['users'], function (i, user) {
  
      var li_entry = "<li class='list-group-item'> <div class='checkbox'> <label> <input id='checkbox-" + user['id'] +"' type='checkbox' value='' checked>"
          + user['surname'] + " " + user['name'] + "</label> </div> </li>";
  
      $('#user_menu').append(li_entry);
  
      $('#checkbox-' + user['id'])
          .click(function() {
              var $this = $(this);
              if ($this.is(':checked')) {
                  console.log('activate layer: ' + user['id']);
  
                  $.each(layer_markers[user['id']], function(i, marker){
                      marker.addTo(map);
                  });
  
  
              } else {
                  console.log('deactivate layer: ' + user['id']);
  
                  $.each(layer_markers[user['id']], function(i, marker){
                      map.removeLayer(marker);
                  });
              }
          });;
  
  });
  
  
  
  $.each(data['tags'], function (i, tag) {
  
      var li_entry = "<li class='list-group-item'> <div class='checkbox'> <label> <input id='checkbox-" + tag['name'] +"' type='checkbox' value='' checked>"
          + tag['name'] + "</label> </div> </li>";
  
      $('#tag_menu').append(li_entry);
  
  
  
      $('#checkbox-' + tag['name'])
          .click(function() {
              var $this = $(this);
              if ($this.is(':checked')) {
                  console.log('activate layer: ' + tag['name']);
  
                  $.each(layer_markers[tag['name']], function(i, marker){
                      marker.addTo(map);
                  });
  
  
              } else {
                  console.log('deactivate layer: ' + tag['name']);
  
                  $.each(layer_markers[tag['name']], function(i, marker){
                      map.removeLayer(marker);
                  });
              }
      });;
  
  });
  