Allows customers to refer friends and earn store credit for each user who registers and/or orders.
You can also give store credit to the refered friends on signup and after first order.
Add to Gemfile:
gem "spree_store_credits" gem "spree_email_to_friend" gem "spree_affiliate"
Run install generators for all extensions:
rails g spree_store_credits:install -f rails g spree_affiliate:install -f