class Git::Base

@git.config('remote.remote-name.push', 'refs/heads/master:refs/heads/master')

otherwise you may have to run something like this first to setup the push parameters:
pushes changes to a remote repository - easiest if this is a cloned repository,

def push(remote = 'origin', branch = 'master', tags = false)
  self.lib.push(remote, branch, tags)
end