code: function initialize(app, options) {
    var log = logger.get(options);
    app._mukoan = app._mukoan || {};
    if (!app._mukoan.initialized) {
      var config = defaults({}, options, DEFAULT_CONFIGURATION);
      log.info('Starting and configuring Koa server');
  
      // Setup global error handler and logger
      app.use(middlewares.error(config.error));
      app.on('error', (error) => log.error('Unexpected exception ', error));
      app._mukoan.initialized = true;
    } else {
      log.warn('Trying to initialize the same Koa instance twice (ignoring action)');
    }
  }
docs: Configures top level middlewares and
  error logging. This should be called before `bootstrap`.
  
  @param  {Object} app A Koa app instance as created by `new Koa()`
  @return {Object}     The `app` instance with middleware already declared.