Render an authorization error if any of Backbone's syncs result with 401 response

gistfile1.coffee

originalSync = Backbone.sync
app = this
Backbone.sync = (method, model, opts) ->
  dfd = $.Deferred()
  if opts
    dfd.then(opts.success, opts.error)

  xhr = originalSync(method, model, _.omit(opts, 'success', 'error'))
  xhr.done(dfd.resolve)
  xhr.fail ->
  if (xhr.status == 401)
    app.auth.error()
    dfd.reject.apply(xhr, arguments)

  return dfd.promise()