code: function Strategy(options, verify) {
  	options = options || {};
  	profileUrl = options.profileURL || null;
  	providerUrl = options.providerURL || null;
  	options.authorizationURL = providerUrl + 'dialog/authorize';
  	options.tokenURL = providerUrl + 'oauth/token';
  	options.scopeSeparator = options.scopeSeparator || ',';
  
  	OAuth2Strategy.call(this, options, verify);
  	this.name = 'signature';
  	this._profileUrl = profileUrl;
  }
docs: `Strategy` constructor.
  
  @param {Object} options
  @param {Function} verify
  @api public