Install NVM , Node and change versions.txt

1. Download the nvm install script via cURL:
    curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.33.0/install.sh | bash

2. Ensure that nvm was installed correctly with nvm --version, which should return the version of nvm installed.
3. Install the version of Node.js you want
      Install the latest version with 
         nvm install node
      Use the latest version with 
          nvm use node
      Install the latest LTS version with 
          nvm install --lts
      Use the latest LTS verison with 
          nvm use --lts