node-chain-gang issue #5

test.js

var chainGang = require('chain-gang');

var chain = chainGang.create();

var task = function(worker) {
    worker.finish();
}

chain.add(task, function(err) {
    console.log('Never called');
});

chain.add(task, undefined, function(err) {
    console.log('I get called');
});