docs: add postgres database

Author: farnabaz

docs/content/1.getting-started/5.migration.md

@@ -19,7 +19,6 @@ Here is the list breaking changes in Content v3:
 - Document driven mode is fully dropped, meaning:
   - Markdown files will not convert to Nuxt pages automatically, you need to create pages, see [how](/components/content-renderer#example)
   - `useContent()`{lang=ts} composable is removed
-  - `useContentHead()`{lang=ts} composable is removed
 - We simplified rendering components.
   - `<ContentDoc>`, `<ContentList>`, `<ContentNavigation>` and `<ContentQuery>` components are dropped in v3.
 - `_dir.yml` files are renamed to `.navigation.yml`

docs/content/1.getting-started/6.configuration.md

@@ -44,6 +44,17 @@ export default defineNuxtConfig({
 ```
 
 
+### `Postgres`
+
+If you plan to deploy your application using PostgreSql database you need to use `postgres` database adapter. 
+```ts [nuxt.config.ts]
+export default defineNuxtConfig({
+  content: {
+    database: { type: 'postgres', url: 'POSTGRES_URL' /* Other options for `pg` */ }
+  }
+})
+```
+
 ## `build`
 
 Nuxt Content read and parse all the available contents at built time. This option let you control over parsing contents.

docs/content/2.usage/.navigation.yml

@@ -1 +1,2 @@
-title: How To Use
+title: How To Use
+icon: i-ph-lightbulb