anchor.diff:  <% provide(:title, "Sign in") %>
  -<h2>Sign in</h2>
  +<h2>登录</h2>
   <div class="container">
        <div class="col-md-4">
        </div>
  
positive.code:   </div>
    <div class="form-group">
    <%= f.submit "Sign in", class: "btn btn-default btn-primart" %>
    </div>
    <% end %>
  </div>
  
negative.code:   <div class="form-group">
    <%= form_for(:session, url: session_path) do |f| %>
    <div class="form-group">
    <%= f.label :name, "用户名", class: "control-label col-sm-1" %>
    <%= f.text_field :name, class: "form-control" %>
    </div>
    <div class="form-group">
  