Let's rephrase this to be more generic:
(Depending on what OS you are running, you might need to install git-core instead of git. You might also need libopenssl-ruby1.8 and libmysqlclient-dev or mysql-devel.)

If these are not available in your default repositories (we've seen this happen with Linux Mint Debian Edition) you might have to add additional repositories. In case of LMDE this did the trick:
```bash
# as root
sudo -s
# add Debian Testing repository in your /etc/apt/sources.list:
echo 'deb http://ftp.debian.org/debian/ jessie main' >> /etc/apt/sources.list
# update the package list
apt-get update
# install the dependency:
apt-get install libmysqlclient-dev
```