Update Deployment docs - resolves #445

doc/20_Deployment.md

@@ -1,11 +1,11 @@
 # Configuration & Deployment
 
-The configuration is saved in `var/config/datahub-configurations.php`.
+The configuration by default is saved in `var/config/data-hub/example.yaml`.
 Additionally, a workspace permission index is kept in the database for better query performance when 
-checking for permissions. 
+checking for permissions.
 
 When deploying configurations following steps are necessary: 
-- Deploy configuration file `var/config/datahub-configurations.php` - e.g. check it into your VCS and 
+- Deploy configuration file `/var/config/.../example.yaml` - e.g. check it into your VCS and 
   deploy it with your deployment mechanisms. 
 
 - Rebuild workspace permission index by running `datahub:graphql:rebuild-definitions`  
@@ -31,6 +31,10 @@ the environment variable `PIMCORE_WRITE_TARGET_DATA_HUB` the storage location ca
 - `settings-store` - write configs to the SettingsStore
 - `disabled` - do not allow to edit/write configs at all
 
+> Important: When using symfony-config write target, configs are written to Symfony
+Config files (yaml), which are only getting revalidated in debug mode. So if you're changing configs in production you
+won't see any update, because these configs are read only.
+
 Details also see [Pimcore Docs](https://pimcore.com/docs/pimcore/current/Development_Documentation/Deployment/Configuration_Environments.html#page_Configuration-Storage-Locations-Fallbacks).
 
 #### Example