code: function(seriesCallback) {
                  var userBoardAlreadyAdded = {};
  
                  for(var i = 0; i < allPinsData.length; i++) {
                      var pin = allPinsData[i];
                      if(pin.board) {
                          var boardUrlParts = pin.board.url.split('/');
                          var user = boardUrlParts[1];
                          var board = boardUrlParts[2];
  
                          if(!userBoardAlreadyAdded[user + board]) {
                              userBoardAlreadyAdded[user + board] = true;
                              boards.push({user: user, board: board});
                          }
                      }
                  }
  
                  seriesCallback();
                  return;
              }
docs: create list of boards that the pins belong to