app.use('/users',users);
router.get('/:user', function(req, res, next) {

app.use('/users/:user',users);
router.get('/', function(req, res, next) {

const app = require("express")()
app.use("/users", require("./routes/users"))

const express = require("express")
const router = express.Router()

router.get('/:user', function(req, res, next) {
    ...
}

module.exports = router

app.use("/", require("./routes/index"))
app.use("/users", require("./routes/users"))
app.use("/ranking", require("./routes/ranking"))
app.use("/bookmarks", require("./routes/bookmarks"))