Cloning this repository:

git clone git://gitorious.org/dokuwiki-piwik/dokuwiki-piwik.git dokuwiki-piwik
cd dokuwiki-piwik

Add this repository as a remote to an existing local repository:

git remote add dokuwiki-piwik git://gitorious.org/dokuwiki-piwik/dokuwiki-piwik.git
git fetch dokuwiki-piwik
git checkout -b my-local-tracking-branch dokuwiki-piwik/master_or_other_branch