diff --git a/compose.yaml b/compose.yaml
index db4d8fb..4568bbf 100644
--- a/compose.yaml
+++ b/compose.yaml
@@ -5,6 +5,8 @@ services:
     restart: unless-stopped
     env_file:
       - .env
+    ports:
+      - "15432:5432"
     volumes:
       - /srv/dttmr-api/postgresql:/var/lib/postgresql/data
     healthcheck:
diff --git a/internal/database/migrations/000002_create_lists.up.sql b/internal/database/migrations/000002_create_lists.up.sql
index ed8ecec..192494f 100644
--- a/internal/database/migrations/000002_create_lists.up.sql
+++ b/internal/database/migrations/000002_create_lists.up.sql
@@ -12,6 +12,7 @@ CREATE TABLE IF NOT EXISTS list_users (
     PRIMARY KEY (list_id, user_id)
 );
 
+CREATE UNIQUE INDEX idx_list_users_list_id_user_id ON list_users(list_id, user_id);
 CREATE INDEX idx_list_users_user_id ON list_users(user_id);
 
 CREATE TABLE IF NOT EXISTS list_items (