add env_vars nobuild

guacamole/config.yaml

@@ -83,6 +83,7 @@ map:
   - ssl:ro
 name: Guacamole Client
 options:
+  env_vars: []
   EXTENSIONS: auth-totp
 panel_admin: false
 panel_icon: mdi:lan
@@ -91,6 +92,9 @@ ports:
 ports_description:
   8080/tcp: web interface
 schema:
+  env_vars:
+    - name: match(^[A-Z0-9_]+$)
+      value: str?
   EXTENSIONS: str?
   TZ: str?
 slug: guacamole