edit.html.eex

<%= form_for @order_changeset, checkout_path(@conn, :update), fn f -> %>
<div class="row">
  <div class="col-md-6 col-md-offset-3">
    <h2>Order Summary</h2>
    <table class="table">
      <thead>
        <tr>
          <th>ID</th>
          <th>Product name</th>
          <th>Pack size</th>
          <th class="text-right">Quantity</th>
          <th class="text-right">Subtotal</th>
        </tr>
      </thead>
      <tbody>
      <%= for {item, i} <- Enum.with_index(@order.line_items, 1) do %>
        <tr>
          <td><%= i %></td>
          <td><%= item.product_name %></td>
          <td><%= item.pack_size %></td>
          <td class="text-right"><%= item.quantity %></td>
          <td class="text-right">₹ <%= item.total %></td>
        </tr>
      <% end %>
      <tr>
        <td colspan=4 class="text-right">Total</td>
        <td class="text-right">₹ <%= @order.total %></td>
      </tr>
      </tbody>
    </table>

    <div class="form-group">
      <%= label f, :comments, class: "control-label" %>
      <%= textarea f, :comments, class: "form-control" %>
      <%= error_tag f, :comments %>
    </div>

    <div class="form-group float-right">
      <%= submit "Confirm", class: "btn btn-primary" %>
    </div>
  </div>
</div>
<% end %>