actually expose the downtime api

lib/index.js

@@ -11,6 +11,7 @@ var metric_api = require('./api/metric.js');
 var search_api = require('./api/search.js');
 var service_check_api = require('./api/service_check.js');
 var snapshot_api = require('./api/snapshot.js');
+var downtime_api = require('./api/downtime.js');
 
 
 var dogapi = function(options){
@@ -27,7 +28,8 @@ extend(dogapi.prototype,
        metric_api.prototype,
        search_api.prototype,
        service_check_api.prototype,
-       snapshot_api.prototype);
+       snapshot_api.prototype,
+       downtime_api.prototype);
 
 dogapi.constants = constants;