'Calls git pull origin <branch> in order to update SickRage. Returns a bool depending
on the call\'s success.'

def update(self):

    self.update_remote_origin()
    if sickbeard.GIT_RESET:
        self.reset()
    if (self.branch == self._find_installed_branch()):
        (stdout_, stderr_, exit_status) = self._run_git(self._git_path, u'pull    -f    {0}    {1}'.format(sickbeard.GIT_REMOTE, self.branch))
    else:
        (stdout_, stderr_, exit_status) = self._run_git(self._git_path, (u'checkout    -f    ' + self.branch))
    if (exit_status == 0):
        self._find_installed_version()
        notifiers.notify_git_update((sickbeard.CUR_COMMIT_HASH or u''))
        return True
    else:
        return False
