Support route parameters in folder names

🚀 Feature Proposal

We should support automatic routes for route params, as example /user/:userId/cart

├── routes
│   ├── user
│   │   ├── _userId
│   │       └── cart.js
├── package.json
└── app.js

I would recommend we convert _ to : on loading.

[jsumners]

With as many customizations this module is getting for hooking into the algorithm, it might just be better to require an autoload.{json,yaml} file that has mappings and other configurations.

[mcollina]

Thanks for the ping, I missed the last round of edit in the PR. It just miss docs.