rss link to url if available

lib/rss.js

@@ -15,11 +15,15 @@ function escapeXml (unsafe) {
 }
 
 const generateRssItem = (item) => {
+  const guid = `${SITE_URL}/items/${item.id}`
+  const link = item.url || guid
   return `
     <item>
       <guid>${SITE_URL}/items/${item.id}</guid>
       <title>${escapeXml(item.title)}</title>
-      <link>${SITE_URL}/items/${item.id}</link>
+      <link>${link}</link>
+      <comments>${guid}</comments>
+      <description><![CDATA[<a href="${guid}">Comments</a>]]></description>
       <pubDate>${new Date(item.createdAt).toUTCString()}</pubDate>
     </item>
   `