code: function Strategy(options, verify) {
    ['domain',
    'clientID',
    'clientSecret',
    'callbackURL'].forEach(function (k) {
      if(!options[k]){
        throw new Error('You must provide the ' + k + ' configuration value to use passport-auth0-oidc.');
      }
    });
  
    options = xtend({}, options, {
      issuer:           'https://' + options.domain + '/',
      authorizationURL: 'https://' + options.domain + '/authorize',
      tokenURL:         'https://' + options.domain + '/oauth/token',
      userInfoURL:      'https://' + options.domain + '/userinfo'
    });
  
    OpenIDConnectStrategy.call(this, options, verify);
  
    this.name = 'auth0-oidc';
  
  }
docs: `Strategy` constructor.
  
  The auth0-oidc authentication strategy authenticates requests by delegating to
  an Auth0 account using the OpenID Connect protocol.
  
  Options:
  - `domain`        your Auth0 Account's domain
  - `clientID`      your Auth0 App's clientID
  - `clientSecret`  your Auth0 App's clientSecret
  - `callbackURL`   URL to which Auth0 will redirect the user after granting authorization
  
  @param {Object} options
  @param {Function} verify
  @api public