title: Starting React App from pulled github project
body: <p>I've pulled a github repository containing code for a reactjs app into one of my directories but I can't find a way to run the app on my computer. I can start a new app using create-react-app but I can't/(don't know how to) use the existing app for instead ofa freshly created one.</p>
  
  <p>I'm running Ubuntu 16.04.3 on a virtual machine, my node version is 4.2.6. 
  I've tried <strong>sudo apt-get install --only-upgrade nodejs</strong> but it simply says my node version is already up to date. (I include this because npm start gives me a bunch of errors and tells me that it may be because I might have to update node) but the app I create with create-react-app works fine?
  The error:
  <a href="https://i.stack.imgur.com/g6aNk.png" rel="noreferrer"><img src="https://i.stack.imgur.com/g6aNk.png" alt="enter image description here"></a>
  Package.json:</p>
  
  <pre><code>{
      "name": "my-app",
      "version": "0.1.0",
      "private": true,
      "dependencies": {
          "bootstrap": "^3.3.7",
          "express": "^4.16.2",
          "package.json": "^2.0.1",
          "prop-types": "^15.6.0",
          "react": "^16.0.0",
          "react-bootstrap": "^0.31.5",
          "react-dom": "^16.0.0",
          "react-router-dom": "^4.2.2",
          "react-scripts": "1.0.14",
          "uuid": "^3.1.0",
          "webpack": "^3.8.1"
          },
      "scripts": {
          "start": "react-scripts start",
          "build": "react-scripts build",
          "test": "react-scripts test --env=jsdom",
          "eject": "react-scripts eject"
          },
      "devDependencies": {
          "babel-cli": "^6.26.0",
          "babel-preset-env": "^1.6.1"
          }
  }
  </code></pre>