add all routers in api/index.js

[bryceAM]

api/index.js

const productsRouter = require('./products');
apiRouter.use('/products', productsRouter);

const usersRouter = require('./users');
apiRouter.use('/users', usersRouter);

const activeCartRouter = require('./activecart');
apiRouter.use('/cart', activeCartRouter);

[bryceAM]

Example

api/index.js

const productsRouter = require('./products');
apiRouter.use('/products', productsRouter);

module.exports = apiRouter;

/index.js

server.use('/api', require('./api'));

These 2 working together will build the route /api/products.