title: Can a Rails app and engine on different base domains share session?
body: <p>I have a Rails app hosted on domain.com and an engine mounted on a different domain using this <em>routes</em> configuration:</p>
  
  <pre><code>Rails.application.routes.draw do
    mount Some::Engine =&gt; '/', as: 'some', constraints: { domain: 'other_domain.com' }
  end
  </code></pre>
  
  <p>Is there any way, no matter how <em>hacky</em>, to have access to the same session on both domains?</p>