I cannot POST using express while following MVC - node.js

Question

I'm trying to build a simple to-do list. I keep getting a cannot POST error trying to add a to-do using a form to submit. I'm not sure if I'm linking my files correctly or not while trying to follow MVC. Am I missing a module?
app.js (trimmed down because SO says I have mostly code)
const express = require("express");
const mongoose = require("mongoose");
const dotenv = require("dotenv");
const exphbs = require("express-handlebars");
const MongoStore = require("connect-mongo");
const connectDB = require("./config/db");
// config.env is where all the global variables are stored.
dotenv.config({ path: "./config/config.env" });
// This call connects to mongodb.
connectDB();
// Initialize app
const app = express();
// Body parser
app.use(express.urlencoded({ extended: false }));
app.use(express.json());
// Handlebars
app.engine(".hbs", exphbs({ extname: ".hbs" }));
app.set("view engine", "hbs");
// Sessions
app.use(
session({
secret: "keyboard cat",
resave: false,
saveUninitialized: false,
store: MongoStore.create({ mongoUrl: process.env.MONGO_URI }),
})
);
// Passport middleware
app.use(passport.initialize());
app.use(passport.session());
// Static folder
app.use(express.static(path.join(__dirname, "public")));
const PORT = process.env.PORT || 3000;
// Routes
app.use("/", require("./routes/index"));
app.use("/auth", require("./routes/auth"));
// app.use("/todo", require("./routes/todo"));
app.listen(
PORT,
console.log(`Server running in ${process.env.NODE_ENV} mode on PORT ${PORT}`)
);
todo.js in Route
const express = require("express");
const router = express.Router();
const todosController = require("../controllers/todos");
// const { ensureAuth, EnsureGuest } = require("../middleware/auth");
router.get("/", todosController.getTodos);
router.post("/addTodo", todosController.addTodo);
todo.js in Controller
const Todo = require("../models/todos");
module.exports = {
addTodo: async (req, res) => {
try {
await Todo.create({
todo: req.body.todoItem,
done: false,
googleId: req.user.googleId,
});
console.log("To do has been added!");
res.redirect("/");
} catch (err) {
console.error(err);
}
},
};
handlebars form
<form class="center" action="/addTodo" method="POST">
<input type="text" placeholder="Add a To Do" name="todo" />
<button type="submit" class="submitButton">
<i class="fa fa-plus-square"></i>
</button>
</form>
and lastly my folder structure