title: Ruby on rails - Simple form not displaying errors for radio select. Other errors display fine
body: <p>I have a user registration form (Devise) with 4 elements; Username, email, password and 'user type'. User type is a boolean and is displayed as a radio select on the form.</p>
  
  <p>Errors for Username, email and password show no problem, but I get no errors showing if a user doesn't select one of the radio buttons. Validation IS in place, and the form won't send without one of the radio buttons selected, but I get no errors.</p>
  
  <p>The form:</p>
  
  <pre><code>&lt;%= simple_form_for(resource, as: resource_name, url: registration_path(resource_name)) do |f| %&gt;
              &lt;%= f.error_notification %&gt;
          &lt;div class="role-selector"&gt;
              &lt;p class="type-sel-txt"&gt;&lt;%= t('front.whattype') %&gt;&lt;/p&gt;
              &lt;label for="artistuser"&gt;
                  &lt;%= f.radio_button :artist, "1", :id =&gt; "artistuser" %&gt;
                  &lt;span class="artistuser-sel"&gt;&lt;%= t('front.bandm') %&gt;&lt;/span&gt;
              &lt;/label&gt;
              &lt;label for="eventuser"&gt;
                  &lt;%= f.radio_button :artist, "0", :id =&gt; "eventuser" %&gt;
                  &lt;span class="eventuser-sel"&gt; &lt;%= t('front.evento') %&gt;&lt;/span&gt;
              &lt;/label&gt;
          &lt;/div&gt;
          &lt;%= f.input :username, required: true, autofocus: true, placeholder: t('forms.login.user'), label: false %&gt;
          &lt;%= f.input :email, required: true, placeholder: t('forms.login.email'), label: false %&gt;
          &lt;%= f.input :password, required: true, placeholder: t('forms.login.password'), label: false %&gt;
          &lt;div id="passcheck"&gt;&lt;/div&gt;
          &lt;%= f.button :submit, t("forms.login.signup"), id: "register-btn" %&gt;
      &lt;% end %&gt;
  </code></pre>
  
  <p>User.rb:</p>
  
  <pre><code>  validates_inclusion_of :artist, in: [true, false], on: :create
  </code></pre>
  
  <p>Registration works without a problem, my only issue is the error not showing. I'm not sure if it is necessary to paste any more of my code, but if so I'll update with whatever is required.</p>