Install git and then checkout code

[luandy64]

Here's the error I saw:

Either git or ssh (required by git to clone through SSH) is not installed
in the image. Falling back to CircleCI's native git client but the
behavior may be different from official git. If this is an issue, please
use an image that has official git and ssh installed.

ssh: no key found

The first section appeared on the last successful run as well.

I rebuilt the container with SSH, connected, and got

root@400194e20721:~# git
-bash: git: command not found

So this PR will install git and then checkout the code

[luandy64]

This was not the solution. Adding deploy keys to Circle was