title: Is `require jquery_ujs` still needed in Rails 5.1?
body: <p>I am installing jQuery in my <code>5.1.x</code> Rails app via the <code>jquery-rails</code> gem.</p>
  
  <p>In the gem setup, they recommend to add these lines to <code>application.js</code> by default: </p>
  
  <pre><code>//= require jquery
  //= require jquery_ujs
  </code></pre>
  
  <p>But, in a Rails <code>5.1.x</code> app, you have already this line which doesn't depend on jQuery anymore:</p>
  
  <pre><code>//= require rails-ujs
  </code></pre>
  
  <p>I suppose both are doing the exact same thing and one is not needed.</p>
  
  <p>Should I keep both anyway or should I prefer only <code>jquery_ujs</code> or only <code>rails-ujs</code>?</p>