title: Ruby on Rails 4 select multiple
body: <p>I have a form that creates new users. I am trying to add a drop down option to select permission levels. I want to be able to select multiple permission levels per user. </p>
  
  <p>This is my view, I added <code>{:multiple =&gt; true}</code> :</p>
  
  <pre><code>&lt;%= f.label :permission, "Permission Level" %&gt;
  &lt;%= f.select :permission, [ ["Read Only", "read"], ["IP Voice Telephony", "ip_voice"], ["IP Video Telephony", "ip_video_telephony"], ["Enterprise Gateways", "enterprise_gateways"], ["Consumer ATAs", "consumer_atas"], ["IP PBX", "ip_pbx"], ["Master of All", "all"] ], {prompt: "Select Permission Level"}, {:multiple =&gt; true}, class: "input-lg" %&gt;
  </code></pre>
  
  <p>My controller, I added <code>:permission =&gt; []</code> :</p>
  
  <pre><code>def user_params
    params.require(:user).permit(:name, :email, :password, :password_confirmation, :admin, :permission =&gt; [])
  end
  </code></pre>
  
  <p>The error I get for my view, f.select:</p>
  
  <pre><code>wrong number of arguments (5 for 2..4)
  </code></pre>
  
  <p>How do you make a select multiple for Rails 4?</p>