index.html.eex

<!-- ... -->
<%= for user <- @users do %>
    <tr>
      <td><img src="<%= MyApp.Avatar.url({user.avatar, user}) %>"/></td>
      <td><%= user.username %></td>
      <td><%= user.email %></td>

      <td class="text-right">
        <%= link "Show", to: user_path(@conn, :show, user), class: "btn btn-default btn-xs" %>
        <%= link "Edit", to: user_path(@conn, :edit, user), class: "btn btn-default btn-xs" %>
        <%= link "Delete", to: user_path(@conn, :delete, user), method: :delete, data: [confirm: "Are you sure?"], class: "btn btn-danger btn-xs" %>
      </td>
    </tr>
<% end %>
<!-- ... -->