Railtie and Require issues

Nice job!

We need to test the railtie config behavior:
* `GlobalID.app` for `Blog::Application` defaults to `'blog'`
* `GlobalID.app` can be set with `config.global_id.app = `
* `SignedGlobalID.verifier` for `Blog::Application` defaults to `Blog::Application.message_verifier(:signed_global_ids)` - can test this by trying to verify a message generated with a different verifier
* `SignedGlobalID.verifier` can be set with `config.global_id.verifier = ` - can test this similarly, check that locating a signed ID works when its signed by that verifier and doesn't work if it was signed by a different verifier