title: Test if User is Logged in In Hamlet template
body: <p>I want to test if the user is authenticated and show a "log in" or "log out" link depending on the state.</p>
  
  <p>So far I have</p>
  
  <pre><code>$maybe muid &lt;- maybeAuthId
      &lt;a href=@{AuthR LogoutR} &gt;Logout
  $nothing
      &lt;a href=@{AuthR LoginR} &gt;Login
  </code></pre>
  
  <p>but I get an error:</p>
  
  <pre><code>Couldn't match expected type `Maybe v0'
              with actual type `GHandler s0 m0 (Maybe (AuthId m0))'
  In the first argument of `Text.Hamlet.maybeH', namely `maybeAuthId'
  </code></pre>