Fixed bug

When name is number then `substring()` cannot be applied.

Author: githubjeka

web/js/app.js

@@ -263,7 +263,7 @@ d3.xhr(routes.items).get(function (error, XMLHttpRequest) {
  group.append("svg:text")
  .attr("class", "nodetext")
  .text(function (d, i) {
- return (d.name.length < 11) ? d.name : d.name.substring(0, 10) + '...';
+ return (d.name.length < 11) ? d.name : d.name.toString().substring(0, 10) + '...';
  }).style("text-anchor", "middle");