add changes

backend/config/db.js

@@ -0,0 +1,74 @@
+const db = require('../models');
+
+/**
+ * Test database connection
+ */
+async function testConnection() {
+  try {
+    await db.sequelize.authenticate();
+    console.log('✅ Database connection verified');
+    return true;
+  } catch (error) {
+    console.error('❌ Database connection failed:', error.message);
+    return false;
+  }
+}
+
+/**
+ * Sync all models with database
+ * WARNING: Use with caution in production
+ */
+async function syncModels(options = {}) {
+  try {
+    await db.sequelize.sync(options);
+    console.log('✅ Models synchronized with database');
+    return true;
+  } catch (error) {
+    console.error('❌ Model synchronization failed:', error.message);
+    return false;
+  }
+}
+
+/**
+ * Close database connection
+ */
+async function closeConnection() {
+  try {
+    await db.sequelize.close();
+    console.log('✅ Database connection closed');
+    return true;
+  } catch (error) {
+    console.error('❌ Failed to close database connection:', error.message);
+    return false;
+  }
+}
+
+/**
+ * Get database statistics
+ */
+async function getDatabaseStats() {
+  try {
+    const [tables] = await db.sequelize.query('SHOW TABLES');
+    const [version] = await db.sequelize.query('SELECT VERSION() as version');
+    
+    return {
+      connected: true,
+      version: version[0].version,
+      tables: tables.length,
+      database: db.sequelize.config.database
+    };
+  } catch (error) {
+    return {
+      connected: false,
+      error: error.message
+    };
+  }
+}
+
+module.exports = {
+  db,
+  testConnection,
+  syncModels,
+  closeConnection,
+  getDatabaseStats
+};