diff --git a/composer.json b/composer.json
index ec44c04..3861c18 100644
--- a/composer.json
+++ b/composer.json
@@ -25,7 +25,8 @@
         "psr/container": "^1.0",
         "symfony/config": "3.4",
         "symfony/process": "^3.4",
-        "monolog/monolog": "^2.0"
+        "monolog/monolog": "^2.0",
+        "symfony/yaml": "^5.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^7.4"