anchor.diff:            <tr>
               <td class='check'><input form ='delete-selected' type='checkbox' name='message_ids[]' value='<%= message.id %>'></td>
               <td class='date'><%= message.created_at.strftime("%D~%H:%M") %></td>
  -            <td class='from'><a class='btn btn-link' href='/friends/<%= message.sender.id %>'><%= message.sender.username %></a></td>
  +            <td class='from'><a class='btn btn-link' href='/friends/<%= message.sender_id %>'><%= message.sender.username %></a></td>
               <td class='title'><%= message.sender.username %> would like to be your friend!</td>
               <td class='action'>
                 <form id='friend' method='post' action='/friends/<%= message.sender_id %>/confirm'>
  
positive.code:               </form>
              </td>
            </tr>
          <% end %>
          <form id='delete-selected' method='post' action='/messages/delete'>
            <input type='hidden' name='_method' value='delete'>
  
negative.code: <div class='outer content-box'>
    <h3><strong>inbox</strong></h3>
      <a href='/messages/new'>
        <button class='btn btn-xs btn-info'>compose
        </button>
      </a> |
      <button class='btn btn-xs btn-danger' form='delete-selected' type='submit'>delete selected
      </button>
      <br><br>
      <span class='text-info'>
        <%= flash[:message_sent] %>
      </span>
      <span class='text-danger'>
        <%= flash[:deleted] %>
      </span>
    <table class='text-center table-striped' width='700px'>
      <tr>
        <th class='text-center check'></th>
        <th class='text-center date'>date</th>
        <th class='text-center from'>from</th>
        <th class='text-center title'>title</th>
        <th class='text-center action'></th>
      </tr>
        <% @messages.each do |message| %>
          <% if message.content == "share recipe" %>
  