JWT in rules

jwt.js

function (user, context, callback) {
  var CLIENT_SECRET = 'TARGET_API_CLIENT_SECRET';  // Target API Client secret
  var CLIENT_ID = 'TARGET_API_CLIENT_ID';

  var jwt_user = {
    user_id: user.id,
    email: user.email,
    name: user.name
  };

  var options = {
     expiresInMinutes: 600, //should match the app's expiration
     audience: TARGET_CLIENT_ID,
     subject: user.user.id
     issuer: 'THIS AUTH SERVER' //e.g. "https://eugeniopace.auth0.com"
  };

  user.id_token = jwt.sign(jwt_user, new Buffer(TARGET_API_CLIENT_SECRET, 'base64'), options);
  callback(null, user, context);
}