diff --git a/mediawiki/stack.yml b/mediawiki/stack.yml
index 84e79c4f5..04e637fb4 100644
--- a/mediawiki/stack.yml
+++ b/mediawiki/stack.yml
@@ -25,4 +25,4 @@ services:
       MYSQL_DATABASE: my_wiki
       MYSQL_USER: wikiuser
       MYSQL_PASSWORD: example
-      MYSQL_RANDOM_ROOT_PASSWORD: yes
+      MYSQL_RANDOM_ROOT_PASSWORD: 'yes'