How the deployment tool works

It can't work as a normal script because of the ssh connections. It executes four phases in each site:

1. When it connects to a site, it executes the code part that must be executed on the site,
2. Then it seeks the next place where to go and if it is ready,
3. It copies the needed data (config files, code files and others) to the site
4. And it calls the next code part on the next site using a SSH command.