app/views/layouts/application.html.erb

<!DOCTYPE html>
<html>
<head>
  <title>Omniauth Popup</title>
  <%= stylesheet_link_tag    'application' %>
  <%= javascript_include_tag 'application' %>
  <%= csrf_meta_tags %>
</head>
<body>
  <header class='main'>
    <h1><%= link_to 'Omniauth Popup', root_path %></h1>
    <nav class='lang-nav'>
      <span><%= t('.language') %>:</span>
      <ul class='lang-items'>
        <li class='lang-item'><%= link_to_unless_current 'English', locale: 'en' %></li>
        <li class='lang-item'><%= link_to_unless_current 'Português', locale: 'pt' %></li>
      </ul>
    </nav>
    <nav class='user-nav'>
      <ul>
        <% if current_user %>
          <li>
            <%= link_to current_user do %>
              <%= image_tag current_user.image, class: 'user-pic' if current_user.image %>
              <%= content_tag :span, current_user.name %>
            <% end %>
          </li>
          <li><%= link_to t('.logout_link'), sign_out_path %></li>
        <% else %>
          <li><%= link_to_login_with 'Facebook', '/auth/facebook', { width: '460', height: '460' } %></li>
          <li><%= link_to_login_with 'GitHub', '/auth/github', { width: '1050', height: '700' } %></li>
          <li><%= link_to_login_with 'Google', '/auth/google', { width: '800', height: '470' } %></li>
          <li><%= link_to_login_with 'Twitter', "/auth/twitter?lang=#{I18n.locale}", { width: '660', height: '710' } %></li>
        <% end %>
      </ul>
    </nav>
  </header>

  <div id='js-messages' class='messages'>
    <% flash.each do |type, message| %>
      <span class='message <%= type %>'>
        <%= message %>
      </span>
    <% end %>
  </div>

  <div class='content'>
    <%= yield %>
  </div>
</body>
</html>