title: how to clear sessions
body: <p>I am using rails 4.2, Mysql</p>
  
  <p>Background:</p>
  
  <p>I was using Webrick server to stage my website online. My database tables were populated and everything worked as i wanted to. I put few items in a cart to check my transaction and..... decided to switch my server to Unicorn. It took me sometime to understand how nginx, unicorn and ubuntu work together. While I was doing that I have decided to give myself a fresh start and (foolishly!) re-created my database schema.</p>
  
  <p>Problem area:</p>
  
  <p>When I restarted my app and clicked on 'Catalogue' menu the following exception appears:</p>
  
  <p><img src="https://i.stack.imgur.com/WL9SA.png" alt="enter image description here"></p>
  
  <p>I used</p>
  
  <pre><code> rake tmp:sessions:clear &amp; rake db:sessions:clear
  </code></pre>
  
  <p>Nothing had happen. Please help me to sort this out. Thank you.</p>