code: function replaceAssociation(req, res) {
    if(redirect(req.params.id, '', '', res)) {
      return;
    }
  
    var id = req.params.id;
    var url = req.body.url;
    var directory = req.body.directory;
    var tags = req.body.tags;
    var position = req.body.position;
    var rootUrl = req.protocol + '://' + req.get('host');
    var queryPath = req.originalUrl;
    req.chickadee.setAssociation(req, id, url, directory, tags, position,
                                 rootUrl, queryPath, function(response, status) {
      res.status(status).json(response);
    });
  }
docs: Replace the specified association.
  @param {Object} req The HTTP request.
  @param {Object} res The HTTP result.