The application is builded in Ruby (v. 2.3.1p112). Application instance has method to fetch database. It gets the source .csv file when instance initialize. This actions are included in the app:fetch_db rake task.
Required gems are included in Gemfile. You can install their with bundler.
The application uses NoSQL database MongoDB. Hence, you have to create new database, which is called like converter. Get more information about MongoDB interactions.
In addition, there is a class ExchangeRateConverter to handle conversion of a USD value date pair to Euro value.
ExchangeRateConverter.convert(100, '2013-01-13')
returns what 100 USD was in euros on January 13, 2013.
Finally, the app is a subject of testing. Using RSpec, you can run tests in spec folder.
I started from implementation of the basic behaviour with RSpec. Eventually, I spent 14 hours for researching and developing. I moved step by step.
Have a nice converting! 💸