diff --git a/compose.postgres.yml b/compose.postgres.yml
index 4285ded..44bb471 100644
--- a/compose.postgres.yml
+++ b/compose.postgres.yml
@@ -1,3 +1,6 @@
+---
+version: '3.8'
+
 # Compose for PostGres mode instead of the default sqlite mode.
 services:
   app: