diff --git a/composer.json b/composer.json
index 527ae1db..da40fa12 100644
--- a/composer.json
+++ b/composer.json
@@ -40,6 +40,7 @@
   "require": {
     "php": ">=5.4",
     "alchemy/zippy": "^0.3",
+    "doctrine/collections": "1.4.0",
     "kevinlebrun/colors.php": "^1.0",
     "michelf/php-markdown": "^1.6",
     "seld/jsonlint": "^1.0",