I file this as a bug and not as a feature request, because
I thought it was supposed to work already:

as demonstrated by opening
   http://mechanicalcat.net:8080/demo
(without the slash at the end!) horrible
things happen if the slash is missing. I just
had a new user who complained loudly
about roundup because he got a very bad
first impression...

Of course it can be avoided easily (and in fact, in this
case the URL I sent him had the slash), but as it seems
to be a very common error roundup should detect the
missing slash and redirect the user to the correct URL.