title: Winston 3.x support for logstash missing?
body: <p>I'm trying to integrate a dummy nodejs app to an ELK stack. I'm using winston as logging library since it's my preferred choice when I develop on a JS stack. I've tried to write this sinppet of code, using winston 3.x version</p>
  
  <pre><code>var winston = require('winston');
  require('winston-logstash');
  
  
  var logger =  winston.createLogger({
      level: 'info',
      transports: [
          new winston.transports.Console(),
          new winston.transports.Logstash({
              port: 5000,
              node_name: 'my node name',
              host: '127.0.0.1'
          })
      ]
  });
  
  logger.info('ciao mondo')
  </code></pre>
  
  <p>The result was</p>
  
  <pre><code>&gt; node index.js
  
  logstash is a legacy winston transport. Consider upgrading: 
  - Upgrade docs: https://github.com/winstonjs/winston/blob/master/UPGRADE-3.0.md
  </code></pre>
  
  <p>So I've read the official instructions which state that the logstash support is now a format</p>
  
  <pre><code>var winston = require('winston');
  require('winston-logstash');
  
  
  var logger =  winston.createLogger({
      level: 'info',
      format : winston.format.logstash(),
      transports: [
           new winston.transports.Console()/*,
           new winston.transports.Logstash({
             port: 5000,
             node_name: 'my node name',
             host: '127.0.0.1'
           })*/
        ]
    });
  
    logger.info('ciao mondo')
  </code></pre>
  
  <p>Now the output is</p>
  
  <pre><code>&gt; node index.js
  
  {"@message":"ciao mondo","@fields":{"level":"info"}}
  </code></pre>
  
  <p>Which is ok, but since I've not told how to connect with logstash socket, the centralized logging system didn't receive this event. </p>
  
  <p>I've tried downograding winston to 2.4.1 and it works fine, excpet for the fact that I'm loosing some good feature introduced in the laters versions. I've not found any documentation that informs about logstash support on 3.x version. Am I missing something or I have to write something custom?</p>