title: Block another user from accessing the Rails application with my authentication
body: <p>I have hosted a rails application, an online examination system. The users need to get registered to get access to the system. So each user will be provided with a unique combination of credentials. Let us assume my <code>user-name/password</code> is <code>demo/demo123</code>. I want my app to block another person logging in to the system even if he knows my credentials. Any solution for such scenario.</p>
  
  <p>Thanks for any help :)-</p>