Document env vars exposed to deployments

Author: yamalight

docs/Advanced.md

@@ -73,6 +73,22 @@ Current caveats:
 - Currently secrets only work for environment variables
 - Currently secrets work only for normal deployments (any template or recipe that uses `startFromParams` won't have secrets expanded)
 
+## Accessing Exoframe data from within the deployed application
+
+Exoframe provides a set of environment variables that are set on each deployment to allow getting project info and settings.  
+Currently those are:
+
+```bash
+# owner of current deployment
+EXOFRAME_USER=admin
+# project of current deployment
+EXOFRAME_PROJECT=projectName
+# full deployment ID
+EXOFRAME_DEPLOYMENT=exo-admin-deployName-ID
+# host used to expose current deployment (if any)
+EXOFRAME_HOST=exo-admin-deployName-ID.baseDomain
+```
+
 ## Plugins
 
 Exoframe-Server supports extension of core features using plugins.