Move training engine to new repo

https://trello.com/c/lXOVnNWD
Update Gemfile with new location

https://trello.com/c/lXOVnNWD
Move custom training app views to main app

https://trello.com/c/lXOVnNWD
Merge branch 'move-training-engine'

* move-training-engine:
  Move custom training app views to main app
  Update Gemfile with new location
  Move training engine to new repo