add monitor api and reorder

lib/api/index.js

@@ -1,10 +1,11 @@
 var api = {
-    tag: require("./tag"),
-    metric: require("./metric"),
     event: require("./event"),
+    infrastructure: require("./infrastructure"),
+    metric: require("./metric"),
+    monitor: require("./monitor"),
     serviceCheck: require("./serviceCheck"),
+    tag: require("./tag"),
     user: require("./user"),
-    infrastructure: require("./infrastructure")
 };
 
 module.exports = function(obj){