Everything worked fine until some guy got the wonderfull idea to put a
"." in his username, and then, all I get is a 404 error, for rails takes
.hk as an extension!
You can restrict what the usernames can include in the model using
validates_format_of
OR
if you want to keep funky usernames, then use the wonderful
permalink_fu plugin to add a permalink attribute to your model. Then,
your map your routes to the permalink instead of the username. It'll
take you 10 minutes, and do all of the hard regular expression work
for you