title: " 'nil' is not an ActiveModel-compatible object. It must implement :to_partial_path " error in micropost model
body: <p>When I attempt to view the user profile page, I get the error above.</p>
  
  <p>Here's my show.html.erb code:</p>
  
  <pre><code>&lt;% provide(:title, @user.name) %&gt;
  
  &lt;div class="row"&gt;
  
    &lt;aside class="span4"&gt;
      &lt;section&gt;
        &lt;h1&gt;
          &lt;%= gravatar_for @user %&gt;
          &lt;%= @user.name %&gt;
        &lt;/h1&gt;
      &lt;/section&gt;
    &lt;/aside&gt;
  
    &lt;div class="span8"&gt;
      &lt;% if @user.microposts.any? %&gt;
        &lt;h3&gt;Microposts (&lt;%= @user.microposts.count %&gt;)&lt;/h3&gt;
        &lt;ol class="microposts"&gt;
          &lt;%= render @microposts %&gt;
        &lt;/ol&gt;
        &lt;%= will_paginate @microposts %&gt;
      &lt;% end %&gt;
    &lt;/div&gt;
  
  &lt;/div&gt;
  </code></pre>
  
  <p>where <code>&lt;%= render @microposts %&gt;</code> is causing the problem. </p>