Docs around middleware only apply to ember-cli-fastboot (?)

[sdhull]

The Request Body section talks about using an in-app-addon to add middleware to your app. This works great with ember-cli-fastboot however it does not work at all if you are deploying to production with the (recommended) Fastboot App Server.

This section should be updated to reflect the different approaches needed for different deployment strategies. Not sure if an in-repo-addon can be used somehow with Fastboot App Server, though I kind of doubt it.