def link(rel, uri, attributes = {})
      headers['Link'] ||= []
      attributes = {:rel => rel}.merge(attributes)
      link = "<#{uri}>"
      attributes.each_pair { |k, v| link << "; #{k}=\"#{v}\"" }
      headers['Link'] << link
    end
def link(rel, uri, attributes = {})
      headers['Link'] ||= []
      attributes = {:rel => rel}.merge(attributes)
      link = "<#{uri}>"
      attributes.each_pair { |k, v| link << "; #{k}=\"#{v}\"" }
      headers['Link'] << link
    end
Generates a Link: header with the specified rel, uri and attributes.
 @param [String, Symbol] rel the relation of the given link
 @param [String] uri the full uri to the specified link resource
 @param [Hash] attributes any other attributes for the link