docs: Use postgresql key name instead of postgres

packages/docs/pages/.vitepress/config.js

@@ -151,6 +151,15 @@ export default defineConfig({
             { text: 'Connection', link: '/apps/openai/connection' },
           ],
         },
+        {
+          text: 'PostgreSQL',
+          collapsible: true,
+          collapsed: true,
+          items: [
+            { text: 'Actions', link: '/apps/postgresql/actions' },
+            { text: 'Connection', link: '/apps/postgresql/connection' },
+          ],
+        },
         {
           text: 'RSS',
           collapsible: true,