Create a restify server changing the `X-Response-Time` header to `X-Runtime` and also changing the value from milliseconds to seconds

gistfile1.js

app = module.exports = restify.createServer({
  name: 'restify',
  version: '1.0.0',
  responseTimeHeader: 'X-Runtime',
  responseTimeFormatter: function(durationInMilliseconds) {
    return durationInMilliseconds / 1000;
  }
});