[API] Implement some Emoji APIs

src/models/emoji.ts

@@ -1,3 +1,4 @@
+import * as mongo from 'mongodb';
 import db from '../db/mongodb';
 
 const Emoji = db.get<IEmoji>('emoji');
@@ -8,6 +9,7 @@ Emoji.createIndex(['name', 'host'], { unique: true });
 export default Emoji;
 
 export type IEmoji = {
+	_id: mongo.ObjectID;
 	name: string;
 	host: string;
 	url: string;