title: Rails 5 whitelist css property for sanitize helper
body: <p>I need to allow inline <code>"style=position: absolute;"</code> output by <code>sanitize(post.content)</code>.   I found <a href="http://apidock.com/rails/v4.0.2/ActionView/Helpers/SanitizeHelper/ClassMethods/sanitized_allowed_css_properties%3D" rel="nofollow noreferrer">documentation for Rails 4</a> that said </p>
  
  <pre><code>config.action_view.sanitized_allowed_css_properties = ['position']
  </code></pre>
  
  <p>in application.rb would add properties to the whitelist, but I can't find documentation whether this is still the case for Rails 5 and it doesn't appear to be working after restarting the server multiple times.  Is there a way to easily add whitelisted css properties?  This <a href="https://stackoverflow.com/questions/21623281/rails-4-disable-automatic-css-sanitizing-when-using-built-in-html-sanitize">answer for Rails 4</a> suggests a monkey patch, but I'm not sure where or how to do so.</p>
  
  <p>Update: installing <a href="https://github.com/kaspth/rails-deprecated_sanitizer" rel="nofollow noreferrer">gem rails-deprecated_sanitized</a> allowed the above config line to work, so it looks like sanitized_allowed_css_properties is deprecated.  Surely there's a way to do this in Rails 5?  I can't step back to 4, and I need to whitelist inline style position in order to get a third party plugin to work (CKEditor + Iframely)</p>