cd ~
apt-get install zsh
zsh
chsh # /bin/zsh
sh -c "$(wget https://raw.github.com/robbyrussell/oh-my-zsh/master/tools/install.sh -O -)"
cd .oh-my-zsh/themes/
nano gitster.zsh-theme
Get content of gitster.zsh-theme
here and write this one.
cd ~
nano .zshrc
Then edit it to use that theme:
ZSH_THEME="gitster"
And restart your terminal.