Updated Ruby version various fixes

[Zakhrov]

Full list of changes

• Downgrade Webpacker from 4.0 to 3.5.0

  • Webpacker 4.0 was giving me errors on asset compilation when building node-sass

• Update Ruby version from 2.5.0 to 2.6.3

• Fix Errors in react transition group

  • react-transition-group has depricated ReactCSSTransitionGroup in favor of TransitionGroup reference

• Update package.json dependencies

  • Update react-addons-css-transition-group to react-transition-group
  • Add emotion, polished, caniuse, draft-js and other dependencies to silence yarn dependency warnings and errors

• Fixes to travis.yml

  • travis builds the app successfully but the rspec tests with Selenium fail