def add_link(relation, href, opts={})
      @links.add relation, Link.new(href, opts)
    end
def add_link(relation, href, opts={})
      @links.add relation, Link.new(href, opts)
    end
Adds link to relation.

 @example
     resource = Halibut::Core::Resource.new
     resource.add_link 'next', '/resource/2', name: 'Foo'
     link = resource.links['next'].first
     link.href
     # => "/resource/2"
     link.name
     # => "Foo"

 @param [String]      relation  relation
 @param [String]      href      href
 @param [Hash]        opts      options: templated, type, name, profile,
                                  title, hreflang