Corrected gridfs api

index.js

@@ -5,6 +5,7 @@
 "use strict";
 
 const mongoose = require('mongoose');
+const gridfs = require('mongoose-gridfs');
 const logger = require('./logger')('error');
 
 mongoose.Promise = global.Promise;
@@ -30,7 +31,7 @@ module.exports = (connectionUri, relaxed) => {
             mongoose.connection = connection;
             module.exports.connection = connection;
 
-            let files_fs = require('mongoose-gridfs')({
+            let files_fs = gridfs.createModel({
                 collection: 'files',
                 model: 'files',
                 mongooseConnection: connection
@@ -38,7 +39,7 @@ module.exports = (connectionUri, relaxed) => {
 
             mongoose.files = files_fs.model;
 
-            let testing_fs = require('mongoose-gridfs')({
+            let testing_fs = gridfs.createModel({
                 collection: 'testing',
                 model: 'testing',
                 mongooseConnection: connection
@@ -46,7 +47,7 @@ module.exports = (connectionUri, relaxed) => {
 
             mongoose.testingFiles = testing_fs.model;
 
-            let solution_fs = require('mongoose-gridfs')({
+            let solution_fs = gridfs.createModel({
                 collection: 'solution',
                 model: 'solution',
                 mongooseConnection: connection