title: Setting the id of a self reference on create using active record
body: <p>Using rails and active record, is it possible to set the id to a self reference on create?</p>
  
  <p>I am coming across an issue where a person is their own supervisor.  I would like to set the supervisor_id field in the create statement for the person.</p>
  
  <pre><code>class Person &lt; ActiveRecord::Base
    belongs_to :supervisor, :class_name =&gt; "Person", :foreign_key =&gt; "supervisor_id"
    ...
  
  Person.create(:name =&gt; "John Smith", :supervisor =&gt; ?self?)
  </code></pre>
  
  <p>From a mysql perspective, I don't see how this is possible in a single query.  Does rails have a built in way to do this?  My current plan is a flag and an after create. </p>