download buildstep container instead of build it

bootstrap.sh

@@ -1,8 +1,9 @@
-# Repository locations - set environment variables to override defaults
-#  e.g. OVERRIDE_DOKKU_REPO=https://github.com/yourusername/dokku.git bootstrap.sh
-GITRECEIVE_URL=${GITRECEIVE_URL:-"https://raw.github.com/progrium/gitreceive/master/gitreceive"}
-BUILDSTEP_REPO=${BUILDSTEP_REPO:-"https://github.com/progrium/buildstep.git"}
+# Source locations - set environment variables to override defaults
+#  e.g. DOKKU_REPO=https://github.com/yourusername/dokku.git bootstrap.sh
 DOKKU_REPO=${DOKKU_REPO:-"https://github.com/progrium/dokku.git"}
+GITRECEIVE_URL=${GITRECEIVE_URL:-"https://raw.github.com/progrium/gitreceive/master/gitreceive"}
+BUILDSTEP_URL=${BUILDSTEP_URL:-"https://raw.github.com/progrium/buildstep/master/buildstep"}
+BUILDSTEP_CONTAINER=${BUILDSTEP_CONTAINER:-"progrium/buildstep"}
 
 # Docker and base dependencies
 apt-get install -y linux-image-extra-`uname -r`
@@ -12,18 +13,19 @@ apt-get update
 apt-get install -y lxc-docker
 apt-get install -y git ruby nginx make
 
-# gitreceive
+# install and init gitreceive
 cd /usr/local/bin
 wget ${GITRECEIVE_URL}
 chmod +x gitreceive
 gitreceive init
 
-# buildstep
-cd ~
-git clone ${BUILDSTEP_REPO}
-cd buildstep
-cp buildstep /home/git/buildstep
-make
+# install buildstep script
+cd /home/git
+wget ${BUILDSTEP_URL}
+chmod +x buildstep
+
+# fetch prebuilt buildstep container
+docker pull ${BUILDSTEP_CONTAINER}
 
 # dokku (this!)
 cd ~