Add database test endpoint for local debugging

🔧 Local Development Debugging:
- Add api/test-db-local.js for database connection testing
- Helps diagnose local environment issues
- Tests table existence and user data

Note: Local Vercel dev having database connection issues
Consider testing on production environment instead

api/test-db-local.js

@@ -0,0 +1,63 @@
+const { Pool } = require('pg');
+
+export default async function handler(req, res) {
+  try {
+    const pool = new Pool({
+      connectionString: process.env.DATABASE_URL,
+      ssl: process.env.NODE_ENV === 'production' ? { rejectUnauthorized: false } : false,
+    });
+
+    const client = await pool.connect();
+
+    // Test basic connection
+    const result = await client.query('SELECT NOW() as current_time');
+    
+    // Test if users table exists
+    const tableCheck = await client.query(`
+      SELECT table_name 
+      FROM information_schema.tables 
+      WHERE table_schema = 'public' 
+      AND table_name IN ('users', 'roles', 'user_roles')
+    `);
+
+    // If users table exists, check for test user
+    let userCheck = null;
+    if (tableCheck.rows.some(row => row.table_name === 'users')) {
+      try {
+        userCheck = await client.query(
+          'SELECT id, username, email FROM users WHERE username = $1',
+          ['testuser']
+        );
+      } catch (err) {
+        userCheck = { error: err.message };
+      }
+    }
+
+    client.release();
+
+    res.status(200).json({
+      success: true,
+      message: 'Database connection test',
+      timestamp: result.rows[0].current_time,
+      environment: {
+        NODE_ENV: process.env.NODE_ENV,
+        has_database_url: !!process.env.DATABASE_URL,
+        has_jwt_secret: !!process.env.JWT_SECRET
+      },
+      tables: tableCheck.rows.map(row => row.table_name),
+      testUser: userCheck ? {
+        exists: userCheck.rows ? userCheck.rows.length > 0 : false,
+        data: userCheck.rows ? userCheck.rows[0] : null,
+        error: userCheck.error || null
+      } : null
+    });
+
+  } catch (error) {
+    console.error('Database test error:', error);
+    res.status(500).json({
+      success: false,
+      error: error.message,
+      stack: error.stack
+    });
+  }
+}