code: func UsersInterfaceRoutes(r *mux.Router, i UsersInterface) {
  	r.HandleFunc("/users", i.Get).Methods("GET")
  	r.HandleFunc("/users", i.Post).Methods("POST")
  	r.HandleFunc("/users/{username}", i.usernameGet).Methods("GET")
  }
docs: // UsersInterfaceRoutes is routing for /users root endpoint