add cron service to obtain oauth token and store it to the DB

models/accessToken.js

@@ -0,0 +1,12 @@
+'use strict';
+
+module.exports = (sequelize, DataTypes) => {
+    const processing = sequelize.define('accessToken', {
+        token: DataTypes.TEXT,
+        validUntil: DataTypes.DATE,
+    }, {});
+    processing.associate = function(models) {
+        // associations can be defined here
+    };
+    return processing;
+};