Retrieve associations for a given URL.

    The associations returned have the exact same structure as defined
    in the ``v1_tag_associate`` route with one addition: a ``tag``
    field contains the full tag name for the association.

def v1_url_associations(tags, url):
    '''Retrieve associations for a given URL.

    The associations returned have the exact same structure as defined
    in the ``v1_tag_associate`` route with one addition: a ``tag``
    field contains the full tag name for the association.
    '''
    url = urllib.unquote_plus(url.decode('utf-8')).strip()
    return {'associations': tags.assocs_by_url(url)}