diff --git a/src/docker.sh b/src/docker.sh
index 604eb1b..75e5a37 100644
--- a/src/docker.sh
+++ b/src/docker.sh
@@ -1,5 +1,5 @@
 build() {
-    docker build --build-arg PHP="$PHP_VERSION" -t "$PHPCTL_IMAGE" .
+    docker build --build-arg PHP="$PHP_VERSION" --build-arg COMPOSER_AUTH="$COMPOSER_AUTH" -t "$PHPCTL_IMAGE" .
 }
 
 push() {