class Middleman::CoreExtensions::DefaultHelpers

`:current_resource` option to customize.
Relative routes will be relative the the current_resource. Pass the

path, respecting :relative_links, directory indexes, etc.
or a Resource, this will produce the nice URL configured for that
Given a source path (referenced either absolutely or relatively)

def url_for(path_or_resource, options={})
  options_with_resource = {}.merge!(current_resource: current_resource).merge!(options)
  ::Middleman::Util.url_for(app, path_or_resource, options_with_resource)
end