[ci skip] Mention dialectOptions in sequelize constructor params

lib/sequelize.js

@@ -56,6 +56,7 @@ module.exports = (function() {
    * @param {Object}   [options={}] An object with options.
    * @param {String}   [options.dialect='mysql'] The dialect you of the database you are connecting to. One of mysql, postgres, sqlite and mariadb
    * @param {String}   [options.dialectModulePath=null] If specified, load the dialect library from this path. For example, if you want to use pg.js instead of pg when connecting to a pg database, you should specify 'pg.js' here
+   * @param {Object}   [options.dialectOptions] An object of additional options, which are passed directly to the connection library
    * @param {String}   [options.storage] Only used by sqlite. Defaults to ':memory:'
    * @param {String}   [options.host='localhost'] The host of the relational database.
    * @param {Integer}  [options.port=] The port of the relational database.