create generic sync wrapper or add to ampersand-collection about ampersand-collection

[aaronmccall]

@funkytek: ampersand-collection and ampersand-state are intentionally persistence-agnostic. If you require an alternate sync strategy to the one provided by ampersand-rest-collection, all you'd need to do is define your own base collection by extending ampersand-collection:

// collections/base.js
var AmpCollection = require('ampersand-collection');
// Your sync strategy
var syncStrategy = require('../helpers/syncStrategy');

module.exports = AmpCollection.extend(syncStrategy);

Then require your base collection instead of ampersand-rest-collection when defining collections:

// collections/people.js
var BaseCollection = require('./base')
var Person = require('../models/person');

module.exports = BaseCollection.extend({
  model: Person
});