Post method for creating new question not working, app just freezes.

'use strict';

const express = require('express');
const app = express();

const routes = require('./routes');

const jsonParser = require('body-parser').json;
const logger = require('morgan');

app.use(logger('dev'));
app.use(jsonParser());

//Mongoose Database:
const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost:27017/qa');

const db = mongoose.connection;

db.on('error', (error) => {
  console.error("connection error: ", error);
});

db.once('open', () => {
  console.log("connection successful");
});

//api url routes
app.use('/questions', routes);

//catch  404 not found errors
app.use((req, res, next) => {
  const error = new Error("Not Found");
  error.status = 404;
  next(error);
});

//custom json error handler
app.use((err, req, res, next) => {
  res.status(err.status || 500);
  res.json({
    error: {
      message: err.message
    }
  });
});

//port and listen
const port = process.env.PORT || 3000;

app.listen(port, () => {
  console.log("working");
});

And here is the code from my routes.js file: 

'use strict';

const express = require('express');
const router = express.Router();
const Question = require("./models").Question;

router.param("qID", (req, res, next, id) => {
  Question.findById(id, (error, doc) => {
    if(error) {
      return next(error);
    }
    if(!doc) {
      error = new Error("Not Found");
      error.status = 404;
      return next(error);
    }
    req.question = doc;
    return next();
  });
});

router.param("aID", (req, res, next, id) => {
  req.answer = req.question.answers.id(id);
  if(!doc) {
    error = new Error("Not Found");
    error.status = 404;
    return next(error);
  }
  return next();
});

// ROUTES FOR QUESTIONS: 

//returns all of the posted questions
router.get('/', (req, res, next) => {
  Question.find({})
    .sort({createdAt: -1})
    .exec((error, questions) => {
      if(error) {
        return next(error);
      }
      res.json(questions);
  });
});

//creating a new question
router.post('/', (req, res, next) => {
  const question = new Question(req.body);
  question.save(function(error, question) {
    console.log('something');
    if(error) {
      return next(error);
    }
    res.status(201);
    res.json(question);
  });
});

//returns a specific quesiton
router.get('/:qID', (req, res, next) => {
  res.json(req.question);
});

// ROUTES FOR ANSWERS: 

//creating an answer
router.post('/:qID/answers', (req, res, next) => {
  req.question.answers.push(req.body);
  req.question.save((error, question) => {
    if(error) {
      return next(error);
    }
    res.status(201);
    res.json(question);
  });
});

//editing an answer
router.put('/:qID/answers/:aID', (req, res, next) => {
  req.answer.update(req.body, (error, result) => {
    if(error) {
      return next(error);
    }
    res.json(result);
  });
});

//deleting an answer
router.delete('/:qID/answers/:aID', (req, res, next) => {
  req.answer.remove((error) => {
    if(error) {
      return next(error);
    }
    req.question.save((error, question) => {
      if(error) {
        return next(error);
      }
      res.json(question);
    });
  });
});

//voting on an answer
router.post('/:qID/answers/:aID/:vote', 
  (req, res, next) => {
    if(req.params.vote.search(/^(vote-up|vote-down)$/) === -1) {
      const error = new Error("Not Found");
      error.status = 404;
      next(error);
    } else {
      req.vote = req.params.vote;
      next();
    }
  }, 
  (req, res, next) => {
    req.answer.vote(req.vote, (error, question) => {
      if(error) {
        return next(error);
      }
      res.json(question);
    });
  });

module.exports = router;