added CLI example for generating types with self-hosted instance

Docs Update. Added a example for generating types with self-hosted
instance.

Co-authored-by: Chris Chinchilla <chris.ward@supabase.io>

apps/docs/content/guides/api/rest/generating-types.mdx

@@ -46,6 +46,12 @@ or in case of local development:
 npx supabase gen types typescript --local > database.types.ts
 ```
 
+or in case of a self-hosted instance (see [Accessing Postgres](/docs/guides/self-hosting/docker#accessing-postgres) for more information):
+
+```bash
+npx supabase gen types typescript --db-url postgres://postgres.[POOLER_TENANT_ID]:[POSTGRES_PASSWORD]@[your-domain-or-ip]:5432/postgres --schema public > database.types.ts
+```
+
 These types are generated from your database schema. Given a table `public.movies`, the generated types will look like:
 
 ```sql