app/overrides/addd_favorite_products_tab_to_users.rb
Deface::Override.new(
virtual_path: 'spree/admin/users/_sidebar',
name: 'add_favorite_products_tab_to_users',
insert_bottom: "[data-hook='admin_user_tab_options']",
text: %Q{
<li<%== ' class="active"' if current == :favorite_products %>>
<%= link_to_with_icon 'th-large', Spree.t(:favorite_product), spree.favorite_products_admin_user_path(@user) %>
</li>
}
)