function getUserIcon(url) {
  return L.icon({
    iconUrl: url || <%= asset_path('marker-red.png').to_json %>,
    iconSize: [25, 41],
    iconAnchor: [12, 41],
    popupAnchor: [1, -34],
    shadowUrl: <%= asset_path('images/marker-shadow.png').to_json %>,
    shadowSize: [41, 41]
  });
}