How session works in Rails
<p>I Learn about session in rails. Most of the reference says that, the following is the way to create a session.</p>

<p>Example: </p>

<pre><code>session[:id]=user.id
</code></pre>

<p>Session is a global hash. My doubt is, if session is a global hash, then If more than one user try's to login, then the session variable gets 
overwrite or not ? Because, there will be only one global hash. So, if millions of user gets login, then how the same "session[:id]" hold
all the users sessions. Is it possible to store more than one value in a single variable. And also how to delete a session for a particular
user. So, how session is handled in rails?</p>