Introduce followed log and following log

src/models/followed-log.ts

@@ -0,0 +1,11 @@
+import { ObjectID } from 'mongodb';
+import db from '../db/mongodb';
+
+const FollowedLog = db.get<IFollowedLog>('followedLogs');
+export default FollowedLog;
+
+export type IFollowedLog = {
+	_id: ObjectID;
+	userId: ObjectID;
+	count: number;
+};