fix(DNS): support proxied property on add

Author: Lukasz Sielski

lib/dns.js

@@ -95,7 +95,7 @@ function add(rr, options) {
   var zid = rr.zoneId;
 
   var uri = join('zones', zid, 'dns_records');
-  var body = pick(rr.toJSON({useAliases: true}), ['type', 'name', 'content', 'ttl']);
+  var body = pick(rr.toJSON({useAliases: true}), ['type', 'name', 'content', 'ttl', 'proxied']);
   options.method = 'POST';
   options.body = JSON.stringify(body);