The Spree Wishlist extension enables multiple wishlists per user, as well as managing those as public (sharable) and private. It also includes the ability to notify a friend via email of a recommended product.
Add the following to your
gem 'spree_wishlist', github: 'spree-contrib/spree_wishlist', branch: 'master'
gem 'spree_email_to_friend', github: 'spree-contrib/spree_email_to_friend', branch: 'master'
$ bundle install
$ bundle exec rails g spree_wishlist:install