title: How to add logout feature to an OpenID enabled site?
body: <p>I have recently added OpenID login to my website. But I don't know how to add the logout feature.</p>
  
  <p>For example, on clicking the Sign In button I am able to show the login form of the selected OpenID provider, for example Google Account. However, I don't know how to implement a Sign Out button to sign out of the Google Account.</p>
  
  <p>Please advice.</p>