title: Heroku git push not updating node modules
body: <p>I am having an issue with pushing my project live on Heroku, as I am currently using "react-animations", and I have done some customization for a specific animation that's inlcuded in the library. In other words, I have edited a .js file in the node_modules folder. On my development server, it runs perfectly. However, when I push it out, the animation is running as default (not modified). What may cause this?</p>
  
  <p>I have tried to reinitialize the git repo, without any luck. Please help me out!</p>