title: What does concat without an object in Rails/Ruby do?
body: <p>I came upon the below code somewhere and can see that it will render a partial using some block. But what does the last part with the <code>concat</code> do?</p>
  
  <pre><code>  def method(stuff="example", &amp;block)
  
      content = render(:partial =&gt; 'some_partial',
          :locals =&gt; { :content =&gt; capture(&amp;block) }
      )
      concat(content)
    end
  </code></pre>