message: lazy-load container-only code
  This is so we can use node 8 features safely inside our container
  environment, without breaking the tests running with node 7
diff: const Koa = require('koa');
  const { Registry, Container } = require('@cardstack/di');
  -const orchestrator = require('./orchestrator');
  -const EmberConnection = require('./ember-connection');
  +// lazy load only in container mode, since they uses node 8 features
  +let EmberConnection;
  +let orchestrator;
  const logger = require('@cardstack/plugin-utils/logger');
  const log = logger('server');
  @@ -37,6 +38,9 @@ async function wireItUp(projectDir, encryptionKeys, seedModels, opts = {}) {
  async function makeServer(projectDir, encryptionKeys, seedModels, opts = {}) {
  if (opts.containerized) {
  log.debug('Running in container mode');
  + // lazy loading
  + orchestrator = orchestrator || require('./orchestrator');
  + EmberConnection = EmberConnection || require('./ember-connection');
  let orchestration = orchestrator.start();
  // Eventually we'll pass a connection instance into the hub, for triggering rebuilds.
  // For now, it just has the side effect of shutting the hub down properly when it's time.
  