code: function gistSha (options, callback) {
    if (!options.id) return callback(new Error('missing option: id'))
  
    var url = '/gists/' + options.id
  
    request({
      url: url,
      qs: {
        access_token: options.token
      }
    }, function (err, json) {
      if (err) return callback(err)
      if (json.message) return callback(new Error(json.message))
      if (json.updated_at) return callback(null, json.updated_at)
      callback(new Error('could not get sha for ' + url))
    })
  }
docs: get the SHA (NOPE: it's just updated_at) of a gist by ID
  
  @param  {object}   options - id, token (optional)
  @param  {Function} callback - err, updated_at?