Composite name in template does not generate plural in table name

I would like to ask a question by following up this post: How to program in Ruby in Portuguese on Rails?

I started studying rails a short time ago and I'm going through a problem with pluralization. When I create the ProductClass template, it generates a migration with the create table product_category command. Should it come product_categories not? If so, how do I fix this? Only change I made was in infletions.rb:

ActiveSupport::Inflector.inflections do |inflect|
  inflect.irregular 'produtocategoria', 'produtocategorias'  
end

But it did not solve the problem. Can you help me?