Use concern to translate models with globalize

_translations.html.haml

# include this partial inside your form
= f.fields_for :translations do |t|
  = t.hidden_field :id
  = t.text_field :locale, readonly: true, label: t('label.locale')
  = t.text_field :name, required: true, label: t('label.name')
        

my_model.rb

class MyModel < ApplicationModel
  # include the concern in all models which should be translated
  include Translations  
  
  # configurate the translation
  translate :name, touch: true, required: true
end

my_models_controller.rb

class MyModelsController < ApplicationController
  def new
    @my_model = MyModel.new.with_locales
  end
  
  private
  
    def my_model_params
      params.require(:my_model).permit(:name, translations_attributes: [:id, :locale, :name])
    end
end

translations.rb

module Translations
  extend ActiveSupport::Concern

  included do
    # class method
    def self.translate(field, args)
      # delegate to globlalize method the configuration
      translates field, args
      
      # to use fields_for at views
      accepts_nested_attributes_for :translations 
    end
  end

  # instance method
  def with_locales
    [:en, :br].each do |locale|
      translations.build(locale: locale)
    end
    self
  end
end