Add /admin page

lib/db.js

@@ -116,6 +116,15 @@ module.exports = class DB {
   }
 
 
+  async updateLastDownload(sid, key) {
+    debug(`Update last download ${sid}++${key}`);
+    const data = this.get(sid).find(item => item.key === key);
+    if(!data) return;
+    data.metadata.lastDownload = Date.now();
+    await this.store.update(`${sid}++${key}`, data);
+  }
+
+
   get(sid) {
     return this.db[sid];
   }