Add RSS feed function

functions/.gitignore

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+node_modules/

functions/index.js

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+const RSS = require('rss');
+const functions = require('firebase-functions');
+const admin = require('firebase-admin');
+
+admin.initializeApp();
+
+exports.feed = functions.https.onRequest(async (req, res) => {
+  const rssFeed = new RSS({
+    title: 'Gunchained videos',
+    description: 'Gods Unchained videos feed',
+    feed_url: 'https://gunchained.app/feed.xml',
+    site_url: 'https://gunchained.app',
+    image_url: 'https://gunchained.app/img/gods-unchained-logo-256.f286f7ea.png',
+    language: 'en',
+    ttl: '60'
+  });
+
+  const querySnapshot = await admin.firestore().collection('videos').orderBy('publishedAt', 'desc').limit(50).get();
+  querySnapshot.forEach(doc => {
+    let id = doc.id;
+    let video = doc.data();
+    let url = `https://gunchained.app/videos/${id}`;
+
+    let item = {
+      title: video.title,
+      description: video.description.substring(0, 300) + '...',
+      url: url,
+      author: video.author,
+      date: video.publishedAt.toDate()
+    }
+    rssFeed.item(item);
+  });
+
+  res.type('application/xml');
+  res.send(rssFeed.xml());
+});