docs: function init(storageConfiguration) {
    var config = storageConfiguration;
    if (!config || !config.mongoUrl) {
      throw Error("Missing mongoUrl parameter for GridFs storage");
    }
    var deferred = q.defer();
    MongoClient.connect(config.mongoUrl, function(err, connection) {
      if (err) {
        console.log("Cannot connect to mongodb server. Gridfs storage will be disabled");
        return deferred.reject(err);
      }
      var gfs = Grid(connection, mongo);
      deferred.resolve(gfs);
    });
    gfsPromise = deferred.promise;
  }