add more slides with details on promises
add more slides with details on promises

nolanlawson/brooklynjs-2016-02,nolanlawson/nyc-camp-2015,nolanlawson/queensjs-2015-11,nolanlawson/queensjs-2015-11,nolanlawson/nyc-camp-2015,nolanlawson/brooklynjs-2016-02,nolanlawson/queensjs-2015-11,nolanlawson/brooklynjs-2016-02,nolanlawson/nyc-camp-2015