refactor: migrate to PostgreSQL + Sequelize

server/models/group.js

@@ -0,0 +1,18 @@
+'use strict'
+
+/**
+ * Group schema
+ */
+module.exports = (sequelize, DataTypes) => {
+  let groupSchema = sequelize.define('group', {
+    name: {
+      type: DataTypes.STRING,
+      allowNull: false
+    }
+  }, {
+    timestamps: true,
+    version: true
+  })
+
+  return groupSchema
+}