title: How can I turn off includeSubDomains for HSTS in rails?
body: <p>I don't want the <code>includeSubDomains</code> option</p>
  
  <pre><code>➔ curl -s --head https://example.com/ |grep Strict 
  Strict-Transport-Security: max-age=15552000; includeSubDomains
  </code></pre>
  
  <p>This doesn't seem to be working:</p>
  
  <pre><code>config.force_ssl = true
  config.ssl_options = { hsts: { subdomains: false } }
  </code></pre>
  
  <p>What am I doing wrong?</p>
  
  <p>Rails 5.0.1</p>