Routes middleware before errorHandler
https://github.com/posquit0/koa-rest-api-boilerplate/blob/1011beebc0672e7a387f0b2b31dbc1569dd10733/app/index.js#L46

I am new to Koa and may be mistaken, but isn't it a problem to have the "routes" middleware registered into the app after the errorHandler middleware? When writing my routes controller I'm experiencing the fact that the errorHandler doesn't capture the status code when it is changed with ctx.throw(409).

My controller looks like this:
```
const create = async (ctx, next) => {
  const { body } = ctx.state
  try {
    const user = await repo.create(body)
    const token = await sign(user.id)
    const view = { token, user: views.main(user) }
    sendResponse = success(ctx, 201)
    sendResponse(view)
  } catch (err) {
    ctx.throw(409, 'fail') // not caught in errorHandler
  }
}
```

The controller is registered into 'koa-router' as follow:
```
const { create } = require('./controller')
router.post('/', create)
```

Changing the order in which routes and errorHandlers are registered into koa solves my issue.