ruby-on-rails – ruby?? on rails gravatar_image_tag

这是user_controller_spec.rb测试：

describe "GET 'show'" do

  before(:each) do
    @user = Factory(:user)
  end

  it "should be successful" do
    get :show,:id => @user
    response.should be_success
  end

end

这是相关的show.html.erb文件：

<table class="profile" summary="Profile information">
  <tr>
    <td class="main">
      <h1>
        <%= gravatar_image_tag(@user.email) %>
        <%= @user.name %>
      </h1>
    </td>
    <td class="sidebar round">
      <strong>Name</strong> <%= @user.name %><br />
      <strong>URL</strong> <%= link_to user_path(@user),@user %>
    </td>
  </tr>
</table>

我得到一个错误,声明“未定义的方法’gravatar_image_tag’.我已经通过执行”gem install gravatar_image_tag“安装了相应的gem,将其添加到我的gemfile中,并执行了”bundle install“.当我执行”gem“时,它被列为已安装清单”

我一直在努力调试这几个小时.任何帮助,将不胜感激.提前致谢.顺便说一下,我正在使用GIT Bash,RubyInstaller-1.9.2-p0运行32位Windows 7.

错误信息：