Add SMS support

Summary:
Provides a working SMS implementation with support for Twilio.

This version doesn't really retry if we get any gruff at all. Future versions should retry.

Test Plan: used bin/sms to send messages and look at them.

Reviewers: chad, epriestley

Reviewed By: epriestley

Subscribers: aurelijus, epriestley, Korvin

Maniphest Tasks: T920

Differential Revision: https://secure.phabricator.com/D8930

externals/twilio-php/Services/Twilio/Rest/UsageTriggers.php

@@ -0,0 +1,27 @@
+<?php
+
+class Services_Twilio_Rest_UsageTriggers extends Services_Twilio_ListResource {
+
+    public function __construct($client, $uri) {
+        $uri = preg_replace("#UsageTriggers#", "Usage/Triggers", $uri);
+        parent::__construct($client, $uri);
+    }
+
+    /**
+     * Create a new UsageTrigger
+     * @param string $category The category of usage to fire a trigger for. A full list of categories can be found in the `Usage Categories documentation <http://www.twilio.com/docs/api/rest/usage-records#usage-categories>`_.
+     * @param string $value Fire the trigger when usage crosses this value.
+     * @param string $url The URL to request when the trigger fires.
+     * @param array $params Optional parameters for this trigger. A full list of parameters can be found in the `Usage Trigger documentation <http://www.twilio.com/docs/api/rest/usage-triggers#list-post-optional-parameters>`_.
+     * @return Services_Twilio_Rest_UsageTrigger The created trigger
+     */
+    function create($category, $value, $url, array $params = array()) {
+        return parent::_create(array(
+            'UsageCategory' => $category,
+            'TriggerValue' => $value,
+            'CallbackUrl' => $url,
+        ) + $params);
+    }
+
+}
+