app/views/bootstrap_view_helpers/_accordions.html.erb
<%= accordion do %>
<%= accordion_group('Collapsible Group Item #1') do %>
One
<% end %>
<%= accordion_group('Collapsible Group Item #2', open: true) do %>
Two
<% end %>
<%= accordion_group('Collapsible Group Item #3') do %>
Three
<% end %>
<% end %>