updated API with new properties for voip_carriers that require outbound registration

lib/models/voip-carrier.js

@@ -33,6 +33,22 @@ VoipCarrier.fields = [
   {
     name: 'e164_leading_plus',
     type: 'number'
+  },
+  {
+    name: 'requires_register',
+    type: 'number'
+  },
+  {
+    name: 'register_username',
+    type: 'string'
+  },
+  {
+    name: 'register_sip_realm',
+    type: 'string'
+  },
+  {
+    name: 'register_password',
+    type: 'string'
   }
 ];