title: Winstonjs does not log any exceptions?
body: <p>I am using Winston to log information in my Koajs application. I have tried to make the default logger to log unhandled exceptions by following the documentation <a href="https://github.com/winstonjs/winston#exceptions" rel="nofollow">here</a>:</p>
  
  <p>But for some reason unhandled exceptions are being logged only if they are thrown from my index.js file. Throwing an exception from one of the routes does not result in winston logging the exception?</p>
  
  <p>Edit:</p>
  
  <p>Here is the code:</p>
  
  <pre><code>let winston = require('winston');
  
  let cassandra = require('cassandra-driver');
  let winstonCassandra = require('../lib/winston_cassandra/index');
  let config = require("../config/config");
  
  let authProvider = new cassandra.auth.PlainTextAuthProvider(config.cassandra.username, config.cassandra.password);
  
  let defaultLoggerOptions = {
    table: "logs",
    level: "debug",
    consistency: cassandra.types.consistencies.one,
    contactPoints: config.cassandra.contactPoints,
    keyspace: config.cassandra.keyspace,
    authProvider: authProvider,
    name: "cassandraDefaultLog"
  };
  
  let errorLoggerOptions = {
    table: "log_exceptions",
    level: "error",
    consistency: cassandra.types.consistencies.one,
    contactPoints: config.cassandra.contactPoints,
    keyspace: config.cassandra.keyspace,
    authProvider: authProvider,
    handleExceptions: true,
    name: "cassandraErrorLog"
  };
  
  winston.add(winstonCassandra, defaultLoggerOptions);
  winston.add(winstonCassandra, errorLoggerOptions);
  
  if(config.env != 'development')
  {
    winston.remove(winston.transports.Console);
  }
  </code></pre>