Add a large example simpler to express

[Raynos]

There would be value if you ported route-seperation or web-service which are larger examples.

That way we can get an idea of how koa is used and how you can structure slightly larger examples. Also the comparison to express is useful for a baseline / similarity.

[jonathanong]

they'll probably be in a separate repos because a lot of features like routes are in separate modules.

[tj]

+1 or a little functioning blogging app or something, I'd like to add acceptance tests to all the examples too like express, it becomes a bit of a PITA when everyone is wondering why certain things don't work anymore

[jonathanong]

migrating to koajs/examples#2