title: Fail to integrate CKeditor in rails_admin gem (use gem rich)
body: <p>I follow the link <a href="https://github.com/bastiaanterhorst/rich#readme" rel="nofollow">GitHub gem rich</a> to install CKeditor to rails_admin
  but I get the error: <code>Unsupported field datatype: rich_editor</code></p>
  
  <p>My model </p>
  
  <pre><code>edit do
          field :title
          field :description, :rich_editor do
            config({
              :insert_many =&gt; true
            })
          end
          field :autho
          field :book_type
        end
  </code></pre>
  
  <p>How can I fix this error? Or that's an issue?</p>
  
  <hr>
  
  <p><strong>EDIT</strong>:
  I tried it, and it worked</p>
  
  <pre><code>field :content, :text do
        ckeditor do true end
  end
  </code></pre>