gsght('set', 'user_id', {
  // The type of id this if for (PSN, XBL, Twitter)
  type: 'user_id',
  // The the id you are trying to set
  id: 'my_game_user_id',
  // optional scope property
  // Used to restrict this id's usage.
  // options: 
  //  - game: This id belongs to this game only (DEFAULT)
  //  - company: This is a company wide id used for many games
  scope: 'game',
  // optional scope id property (when using company scope type)
  scope_id: 'my_company',
  // optional parameter to control hashing of external ID
  // options:
  //  - null: The ID is stored in plain text (DEFAULT)
  //  - server: The ID is hashed on the server-side before being saved
  sha256: 'server'

// To set multiple IDs specify them in an array.
gsght('set', 'user_id', [
  // use this id type for your in-game user id
  {type: 'user_id', id: 'in_game_user_id'},
  // External ids from outside networks
  {type: 'psid', id: 'playstation_network_online_id'},
  {type: 'xbgt', id: 'xbl_gamertag'},
  {type: 'xuid', id: 'xb_user_id'},
  {type: 'twitter', id: 'twitter_name'},
  {type: 'twitch', id: 'twitch_name'},
  // name your own network if using something else
  {type: 'MY_NETWORK_NAME', id: 'my_own_network_id'},
  // hashing example
  {type: 'MY_NETWORK_NAME', id: 'my_own_network_id', sha256: 'server'},

The set command can also be used to control debug levels.

// enable debug warnings (disabled by default)
// when enabled, commands will log warnings to the console when 
// they receive poorly formatted / incomplete options
gsght('set', 'warnings', true)