title: rails_admin setting current_user in controller
body: <p>I have a Event model:</p>
  
  <pre><code>class Event &lt; ActiveRecord::Base
    belongs_to :author, class_name: 'User'
  end
  </code></pre>
  
  <p>I can type in console:</p>
  
  <pre><code>e=Event.last
  e.author
  </code></pre>
  
  <p>In rails_admin when I create a new Event I don't want to show the author_id field in the form. I want to set the author in the controller with something like this:</p>
  
  <pre><code>@e=Event.new(params)
  @e.author_id=current_user.id
  @e.save
  </code></pre>
  
  <p>Is possible to do it in rails_admin?</p>
  
  <p>I have found this <a href="https://github.com/sferik/rails_admin/wiki/How-to-set-current_user-to-the-field" rel="nofollow">document</a> in the official wiki, but i don't want to use the cancan ability and i don't want to set the author_id field with a hidden field in the form becouse is dangerous for the security, infact the POST request can be override with a custom author_id.
  I want simple assign the author_id in a controller. 
  Is possible?</p>