code: function postFile (options) {
    options.hash = _private.getDevHash(options.secret);
    return _private.makeRequest(_getUploadOptions(options),
      'Unable to upload document');
  }
docs: Post translations file form service
  @param  {Object}  options
  @param  {Number}  options.projectId Project ID
  @param  {String}  options.format File format (see documentation)
  @param  {String}  options.content File to upload
  @param  {Boolean} options.keepStrings Keep previous, non present in this file strings
  @param  {String}  options.secret Private key to OneSky API
  @param  {String}  options.apiKey Public key to OneSky API
  @param  {String}  options.language Language of the uploaded file
  @param  {String}  options.fileName Name of the uploaded file