title: Delete Session Cookies Across Multiple Subdomains in Rails 3
body: <p>I'm building a rails app that works similar to Wufoo. When you sign up you get a subdomain, and you can log in on the home page. The app is working, so that when you log in, you get redirected to your subdomain. The problem is that I can't delete the session on both domains. If you log out at (username.myapp.com), it stays logged in at (myapp.com) and vice versa.</p>
  
  <p>Right now I'm using <code>session[:user_id] = nil</code> to delete the session. Is there a way to delete all the sessions across all domains.</p>
  
  <p>In addition, I appended <code>:domain =&gt; :all</code> to my <code>session_store.rb</code> file so I could stay logged in across multiple subdomains.</p>