Sync after generating Twitter images

src/app/twitter/twitter.js

@@ -1,9 +1,16 @@
-const { canTweet } = require('./client');
+const S3Syncer = require('../sync/S3Syncer');
+const { canSync } = require('../sync');
 const tweets = require('./tweets');
 
 async function maybePostTweets() {
+    const syncer = canSync() ? new S3Syncer() : null;
+
     for (let tweet of tweets)
         await tweet.maybePostTweet();
+
+    if (syncer) {
+        await syncer.upload();
+    }
 }
 
 async function testScreenshots() {