class Loofah::Scrubbers::NoReferrer

scrub!(:noreferrer)

:noreferrer adds a rel=“noreferrer” attribute to all links

link_farmers_markup = "ohai! <a href='http://www.myswarmysite.com/'>I like your blog post</a>"
Loofah.html5_fragment(link_farmers_markup).scrub!(:noreferrer)
=> "ohai! <a href='http://www.myswarmysite.com/' rel="noreferrer">I like your blog post</a>"