Group routing

[joefazee]

it will be cool to have group routing instead of us doing

`r := mux.Classic()

    r.HandleFunc(http.MethodGet, "/admin/home",  adminHomeHandler)
     r.HandleFunc(http.MethodGet, "/admin/profile",  adminProfileHandler)`

We can just have maybe admin := mux.Group("admin") then admin.HandleFunc(http.MethodGet, "/home", adminHomeHandler)

Just a thought