ENV is used to help switch settings based on where the application is being run. Default is "development".
App is where all routes and middleware for buffalo should be defined. This is the nerve center of your application.
Routing, middleware, groups, etc... are declared TOP -> DOWN. This means if you add a middleware to `app` *after* declaring a group, that group will NOT have that new middleware. The same is true of resource declarations as well.
It also means that routes are checked in the order they are declared. `ServeFiles` is a CATCH-ALL route, so it should always be placed last in the route declarations, as it will prevent routes declared after it to never be called.
HomeHandler is a default handler to serve up a home page.