app/views/layouts/_login_modal.html.erb
<div class="modal" id="login_modal">
<div class="modal-content row">
<p>
<h5>Sign in with:</h5>
</p>
<% sign_in_provider.each do |provider, helper| %>
<div class="col l4 m4 offset-l1 offset-m1 s8 offset-s2 sso_option">
<%= link_to signin_path(provider.to_s), class: "waves-effect waves-light btn #{helper[:class]}" do %>
<%= "#{content_tag :i, nil, class: "fa #{helper[:icon_class]} left"} #{helper[:name]}".html_safe %>
<% end %>
</div>
<% end %>
</div>
</div>