anchor.diff:    
     <br>
     
  -  <%= link_to 'New User', new_user_path %>
  +  <% if current_user.admin? %><%= link_to 'New User', new_user_path %><% end %>
   </div>
positive.code:         <tr>
            <td><strong><%= link_to user.name, user %></strong></td>
            <td><%= user.admin %></td>
            <td><%= link_to 'Edit', edit_user_path(user) %></td>
            <td><%= link_to 'Destroy', user, method: :delete, data: { confirm: 'Are you sure?' } %></td>
          </tr>
        <% end %>
      </tbody>
  
negative.code:       <tr>
          <th>Name</th>
          <th>Admin?</th>
          <% if current_user.admin? %><th colspan="2"></th><% end %>
        </tr>
      </thead>
    
  