Update README with commands for trusted domains

Added useful commands for managing trusted domains in self-hosted servers.

Author: quochuydev

readme.md

@@ -23,6 +23,28 @@ yarn dev
 
 ![Create service user token](./docs/service-user-token.png)
 
-**Example**
+### Commands
+
+_Useful command to add a trust domain in self host server_
+
+```
+# Add a trusted domain
+docker ps
+
+docker exec -it zitadel_postgres_container_id psql -U postgres -c "\l"
+
+docker exec -it zitadel_postgres_container_id psql -U postgres -d zitadel -c "SELECT * FROM projections.instance_trusted_domains;"
+
+docker exec -it zitadel_postgres_container_id psql -U postgres -d zitadel -c "INSERT INTO projections.instance_trusted_domains (instance_id, creation_date, change_date, sequence, domain) VALUES ('instance_ids', NOW(), NOW(), 1, 'zitadel-login-ui-v2.vercel.app');"
+
+# Verify trusted domain
+curl https://system-v1-fpms4l.zitadel.cloud/.well-known/openid-configuration \
+-H 'x-zitadel-public-host: zitadel-login-ui-v2.vercel.app'
+
+curl https://zitadel-login-ui-v2.vercel.app/.well-known/openid-configuration
+```
+
+### Demo
 
 https://zitadel-login-ui-v2.vercel.app
+