Moving models and interactors into their own modules/directories.
Cleaning up spec.
First step of command line script.
First steps to valid args to CLI interface.
Changing sort argument to be required.

This will make the validation easier.
Adding check for file existing, cleaning up and adding more tests for number of args and file existence.
Changing to require_relative to include files.
Cleaning up knowledge of sort options.
Fleshing out CLI script and adding file of sample records for testing.
DRYing up error handling.