Webpack Configuration: No dist folder, 'cannot GET /' error

I'm following along with a Pluralsight tutorial that deals with manually configuring Babel and Webpack in a React app. I'm not new to React, but I am new to manually configuring Babel and Webpack. I've followed the tutorial but I am getting a cannot GET / error when running the app via npm run dev. I've also noticed that after running npm run build Webpack did not automatically generate a dist folder and I believe that is my problem.

Here is my webpack.config.js file:

// import path from 'path';
const path = require("path");

// export default {
module.exports = {
    mode: 'development',
    entry: path.resolve(__dirname, 'src','app'),
    output: {
        path: path.resolve(__dirname,'dist'),
        filename: 'bundle.js',
        publicPath: '/',
    },
    resolve: {
        extensions: ['.js','.jsx']
    },
    devServer: {
        historyApiFallback: true
    },
    module: {
        rules: [{
            test: /\.jsx?/,
            loader:'babel-loader'
        }]
    }
}

Here is my babel.rc file (which I don't think is the problem but I'll include it anyway):

{
    "presets": [
      ["@babel/preset-env",{
        "targets":{
          "node":"current"
        }
      }],
      "@babel/preset-react"
    ]
}

Here is my package.json file:

{
  "name": "react-fullstack",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "webpack",
    "dev": "webpack-dev-server --open"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@babel/core": "^7.0.0",
    "@babel/node": "^7.0.0",
    "@babel/preset-env": "^7.0.0",
    "@babel/preset-react": "^7.0.0",
    "@babel/register": "^7.0.0",
    "babel-loader": "^8.0.2",
    "webpack": "^4.17.2",
    "webpack-cli": "^3.1.2",
    "webpack-dev-server": "^3.1.7"
  }
}

Why am I getting a cannot GET / error? Is it due to the missing dist folder? How can I correct this and get my app to bundle and run correctly?

I believe maybe there is a problem with the file path in the output.path part of the Webpack config or an issue with the fileName.