title: Rails: Form Object not finding I18n on activemodel (namespacing issue)
body: <p>I have a form object (rails 3) and I am trying to get use <code>config/locales/en.yml</code> for the error messages.</p>
  
  <p>My form object looks like this:</p>
  
  <pre><code>class Users::PasswordAndLoginUpdatingForm
    include Virtus.model
  
    extend ActiveModel::Naming
    include ActiveModel::Conversion
    include ActiveModel::Validations
  
    attribute :requested_email_address, String
    validates :requested_email_address, allow_blank: true, format: { with: User::VALID_EMAIL_REGEX }
  </code></pre>
  
  <p>In my form I have the usual</p>
  
  <pre><code>form_for @form_object ... do |f|
  </code></pre>
  
  <p>If I <code>pry</code> in and find out what the <code>f.object_name</code> is I get <code>users_password_and_login_updating_form</code></p>
  
  <p>Finally, my <code>config/locales/en.yml</code> looks like this:</p>
  
  <pre><code>en:
    activemodel:
      errors:
        models:
          users_password_and_login_updating_form:
            attributes:
              requested_email_address:
                invalid: "bar"
  </code></pre>
  
  <p>The issue I'm having is, I cannot get it to use the internationalization. </p>