docs: function writeFile(namespace, fileName, fileLocation) {
    if (!gfsPromise) {
      return;
    }
    return gfsPromise.then(function(gfs) {
      var deferred = q.defer();
      var options = {
        filename: fileName
      };
      if (namespace) {
        options.root = namespace;
      }
      var writeStream = gfs.createWriteStream(options);
      writeStream.on('error', function(err) {
        console.log('An error occurred!', err);
        deferred.reject(err);
      });
      writeStream.on('close', function(file) {
        deferred.resolve(file);
      });
      fs.createReadStream(fileLocation).pipe(writeStream);
      return deferred.promise;
    });
  }