diff --git a/Dockerfile b/Dockerfile
index e01f641..b8e7279 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -57,4 +57,4 @@ EXPOSE 5432
 CMD ["postgres","-c","listen_addresses=*"]
 
 HEALTHCHECK --interval=30s --timeout=3s --retries=4 \
-  CMD pg_isready -U ${POSTGRES_USER:-postgres}
+  CMD pg_isready -U postgres