Fix apt-get update in docker.sh
diff --git a/debian-8/scripts/docker.sh b/debian-8/scripts/docker.sh
index 9e06fb9..dc543e4 100644
--- a/debian-8/scripts/docker.sh
+++ b/debian-8/scripts/docker.sh
@@ -1,5 +1,6 @@
 # This should simulate preseed behavior
 
+apt-get update
 apt-get -y install curl
 
 # Kernel makes no sense in docker, let base.sh know