diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index ff3308e31..10a843af2 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -6,7 +6,7 @@ variables: &global_variables
   POSTGRES_USER: postgres
   POSTGRES_PASSWORD: postgres
   DB_HOST: postgres
-  DB_PORT: 5432
+  DB_PORT: "5432"
   MIX_ENV: test
 
 workflow: