title: Command to clear the cookie-based session store in Rails
body: <p>I often want to clear the session store in Rails, in particular, the default cookie-based session store.  Some sites seem to suggest that</p>
  
  <pre><code>rake tmp:sessions:clear
  </code></pre>
  
  <p>accomplishes this task, but it appears that it does not.  What is the proper way to clear the cookie-based session store?</p>