code: function queue(options, callback) {
  
  
          // if skipDuplicates, don't crawl twice the same url
          if (options.skipDuplicates) {
              store.getStore().checkInCrawlHistory(options.url, function(error, isInCrawlHistory) {
  
                if (isInCrawlHistory) {
                    log.debug({"url" : options.url, "step" : "queue-resquester.queue", "message" :  "Don't crawl this url - Option skipDuplicates=true & the url has already been crawled" });
                    callback();
                }
                else {
  
                    //numOfUrl++
                    //console.log("Queue length : " + requestQueue.length() + " - Running : " + requestQueue.running() + " - Total Add :" + numOfUrl + " - Total End : " + endUrl + " url : " + options.url );
                    log.debug({"url" : options.url, "step" : "queue-resquester.queue", "message" : "Add in the request queue"});
                    requestQueue.push(options);
                    callback();
  
                }
  
              });
  
          }
          else {
              //numOfUrl++
              //console.log("Queue length : " + requestQueue.length() + " - Running : " + requestQueue.running() + " - Total Add :" + numOfUrl + " - Total End : " + endUrl + " url : " + options.url );
  
              log.info({"url" : options.url, "step" : "queue-resquester.queue", "message" : "Add in the request queue"});
              requestQueue.push(options);
              callback();
          }
  
    }
docs: Add a new url to crawl in the queue.
  Check the desired options and add it to the request queue
  
  @param the options used to crawl the url