Adjust docs according to new getting satrted

src/pages/selfhosted/maintenance/scaling/migrate-sqlite-to-postgresql.mdx

@@ -95,14 +95,15 @@ server:
 
   store:
     engine: "postgres"
+    dsn: "host=postgres-server user=postgres password=password dbname=postgres port=5432"
 ```
 
-Then pass the PostgreSQL connection string as an environment variable in your `docker-compose.yml`:
+Alternatively, you can pass the connection string as an environment variable instead of putting it in the config file:
 
 ```yaml
   netbird-server:
     environment:
-      - NETBIRD_STORE_ENGINE_POSTGRES_DSN=postgres://postgres:password@postgres-server:5432/postgres
+      - NETBIRD_STORE_ENGINE_POSTGRES_DSN=host=postgres-server user=postgres password=password dbname=postgres port=5432
 ```
 
 ## Restart and Verify