app/views/categories/index.html.erb
<h1>Listing categories</h1>
<% if user_signed_in? && current_user.permission == "admin"%>
<table>
<thead>
<tr>
<th>Name</th>
<th>Description</th>
<th colspan="3"></th>
</tr>
</thead>
<tbody>
<% @categories.each do |category| %>
<tr>
<td><%= category.name %></td>
<td><%= category.description %></td>
<td><%= link_to 'Show', category %></td>
<td><%= link_to 'Edit', edit_category_path(category) %></td>
<td><%= link_to 'Destroy', category, method: :delete, data: { confirm: 'Are you sure?' } %></td>
</tr>
<% end %>
</tbody>
</table>
<br>
<%= link_to 'New Category', new_category_path %>
<% end %>