Add constraint to route

[waghanza]

Hi @tbrand,

It could be useful to add some path constraint to routes, I mean adding a regex (or else to allow / or not some pathes).

For example, adding /user/:id(\\d+), create a route for /user/0, /user/1... but not/user/a`

WDYT ?

PS : This example is taken from kitura

[tbrand]

Yeah I agree. :+1: I don't know I could make the time for it. 😢 So anybody please send a PR for this! :pray: lol