feat(core_update_developer_track): upload developer track build

a utility to make uploading the developer-track from an SDK easier.
Usage can be found by simply running the command with no arguments.

core_update_developer_track.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+
+usage="
+usage: $0 <image.bin> <api key>\n
+\n
+Setting everything up for use\n
+1) Run 'gsutil config' and use project id coreos.com:core-update-storage\n
+2) Ensure core-admin is installed, it is a recent addition\n
+"
+
+FILE=$1
+KEY=$2
+
+if [ $# -ne 2 ]; then
+  echo -e $usage
+  exit
+fi
+
+if [ ! -f $FILE ]; then
+  echo "ERROR: No such file $FILE"
+  echo -e $usage
+  exit
+fi
+
+cros_generate_update_payload --image $FILE --output /tmp/update.gz
+MD5SUM=$(md5sum $FILE | cut -f1 -d" ")
+core-admin new-version -k $KEY -v 9999.0.0 -a {87efface-864d-49a5-9bb3-4b050a7c227a} -t developer-build -p $MD5SUM /tmp/update.gz
+gsutil cp /tmp/update.gz gs://update-storage.core-os.net/developer-build/$MD5SUM/update.gz