Fix bug

src/api/serializers/app.ts

@@ -8,6 +8,7 @@ import deepcopy = require('deepcopy');
 import App from '../models/app';
 import User from '../models/user';
 import AccessToken from '../models/access-token';
+import config from '../../conf';
 
 /**
  * Serialize an app

src/api/serializers/drive-file.ts

@@ -7,6 +7,7 @@ import * as mongo from 'mongodb';
 import DriveFile from '../models/drive-file';
 import serializeDriveTag from './drive-tag';
 import deepcopy = require('deepcopy');
+import config from '../../conf';
 
 /**
  * Serialize a drive file

src/api/serializers/user.ts

@@ -8,6 +8,7 @@ import deepcopy = require('deepcopy');
 import User from '../models/user';
 import Following from '../models/following';
 import getFriends from '../common/get-friends';
+import config from '../../conf';
 
 /**
  * Serialize a user