title: Capybara: How do I fill in a input field by its ID
body: <p>I have this:</p>
  
  <pre><code>&lt;input class="string optional" 
      id="course_group_courses_attributes_2_name" 
      name="course_group[courses_attributes][2][name]" 
      placeholder="Lengua" 
      size="15" 
      type="text" /&gt;
  &lt;/div&gt; 
  </code></pre>
  
  <p>How do I fill in a that field by its ID?</p>