title: Set 'Access-Control-Allow-Origin' for multiple domains in Rails 4 application.rb
body: <p>In my Rails app, I set CORS to allow <code>http://someurl.com</code>. What is the syntax for allowing multiple domains?</p>
  
  <p>My current config in <code>application.rb</code></p>
  
  <pre><code>    config.action_dispatch.default_headers = {
          'X-Frame-Options' =&gt; 'ALLOWALL',
          'Access-Control-Allow-Origin' =&gt; 'http://someurl.com', # How can I add "anotherurl.com" to this list?
          'Access-Control-Allow-Credentials' =&gt; 'true',
          'Access-Control-Allow-Methods' =&gt; 'POST GET'
      }
  </code></pre>
  
  <p>The syntax is not mentioned in the guides: <a href="http://edgeguides.rubyonrails.org/configuring.html" rel="noreferrer">http://edgeguides.rubyonrails.org/configuring.html</a></p>