https://github.com/danielevans/handlebars-mode.git
git clone 'git://github.com/danielevans/handlebars-mode.git'
Based on mustache-mode https://github.com/mustache/emacs
In your shell:
mkdir -p ~/.emacs.d/vendor
cd ~/.emacs.d/vendor
curl --location -O https://raw.github.com/danielevans/handlebars-mode/master/handlebars-mode.el
In your Emacs config (normally ~/.emacs):
(add-to-list 'load-path "~/.emacs.d/vendor/")
(require 'handlebars-mode)