diff --git a/hooks/build b/hooks/build
index 7ac4900..f204d16 100644
--- a/hooks/build
+++ b/hooks/build
@@ -1,3 +1,3 @@
 #!/bin/bash
 
-docker build -t $IMAGE_NAME . --build-arg CACHE_TAG=$CACHE_TAG
+docker build -t $IMAGE_NAME . --build-arg CACHE_TAG=${IMAGE_NAME#*:}