Added option "rotatePattern" in order to write logs on ElasticSearch date-rotate indexes.
Use example:
---
var winston = require('winston'),
Elasticsearch = require('winston-elasticsearch'),
var esStatusLogger = new (winston.Logger)({
    transports: [
        new Elasticsearch({
            port: 9200
            indexName: 'index',
            rotatePattern: '.yyyy-MM-dd',
            host: 127.0.0.1,
            disable_fields: true
        })
    ]});
---