def append_slash(url):
    """Make sure we append a slash at the end of the URL otherwise we
    have issues with urljoin Example:
    >>> urlparse.urljoin('http://www.example.com/api/v3', 'user/1/')
    'http://www.example.com/api/user/1/'
    """
    if url and not url.endswith('/'):
        url = '{0}/'.format(url)
    return url
