I install Globally on my Mac
git clone git@github.com:zmon/Site-Org.git
cd Site-Org
git checkout composer
composer install
you sould see something simular to the following:
Loading composer repositories with package information
Installing dependencies (including require-dev)
- Installing commonaccord/ccmac (dev-master 6d54920)
Cloning 6d54920dbb67f75c9bed957abdc9969325cc3c2b
Writing lock file
Generating autoload files
You should be good to go.