Tidy up tutorial

Issue #88 resolved
repo owner created an issue

The tutorial includes code with the following comment. We should tidy this up so it's not necessary to override prepare() - the need to do this suggests a bug elsewhere.

{{{ # This controller registration does not generally have to occur inside # 'prepare', but we place it here so we're sure the middleware has # been initialized by tw2.devtools.dev_server before we make demands of it. }}}