Api url on Exchange Rate Api.io has changed to https://api.exchangeratesapi.io/latest
So in code, u need to replace https://exchangeratesapi.io/api/latest with https://api.exchangeratesapi.io/latest (add.rb, base.rb, convert.rb and remove.rb)
Maybe this could be replaced by some variable so in case of this change u don't need to replace it on 6 places
Cheers,
DD