update backend

models/Vocab.js

@@ -1,5 +1,6 @@
 const { DataTypes } = require('sequelize');
 const { sequelize } = require('../config/database');
+const Grade = require('./Grade');
 
 const Vocab = sequelize.define('Vocab', {
     vocab_id: {
@@ -36,6 +37,11 @@ const Vocab = sequelize.define('Vocab', {
       defaultValue: '',
       comment: 'Vietnamese meaning'
     },
+    Grade_number: {
+      type: DataTypes.INTEGER,
+      defaultValue: 0,
+      comment: 'Numeric representation of grade unit lesson as GG UU LL for easier querying and sorting'
+    },
     category: {
       type: DataTypes.STRING(100),
       comment: 'Category of the word (e.g., Action Verbs, Nouns)'