app/views/answers/edit.html.erb
<%= content_for :title do %>解答を編集<% end %>
<div class="page-header">
<h1><i class="fa fa-edit"></i> 解答を編集</h1>
</div>
<%= render 'form' %>
<hr>
<p>
<%= link_to answer_path(@answer), class: 'btn btn-info btn-sm' do %>
<i class="fa fa-arrow-left"></i> 戻る
<% end %>
</p>