Sequelize store broken with sequelize 5

[armellarcier]

Use of global.sequelize and of $lte operator.

I use this patch (with patch-package)

diff --git a/node_modules/koa2-ratelimit/src/SequelizeStore.js b/node_modules/koa2-ratelimit/src/SequelizeStore.js
index f5bceb4..ac3b23b 100644
--- a/node_modules/koa2-ratelimit/src/SequelizeStore.js
+++ b/node_modules/koa2-ratelimit/src/SequelizeStore.js
@@ -1,4 +1,5 @@
 const Sequelize = require('sequelize');
+const Op = Sequelize.Op;
 
 const Store = require('./Store.js');
 
@@ -116,7 +117,7 @@ class SequelizeStore extends Store {
     }
 
     async _increment(table, where, nb = 1, field) {
-        return table.update({ [field]: global.sequelize.literal(`${field} + ${nb}`) }, { where });
+        return table.update({ [field]: this.sequelize.literal(`${field} + ${nb}`) }, { where });
     }
 
     // remove all if time is passed
@@ -124,7 +125,7 @@ class SequelizeStore extends Store {
         const now = new Date();
         await table.destroy({
             where: {
-                date_end: { $lte: now.getTime() },
+                date_end: { [Op.lte]: now.getTime() },
             },
         });
     }