* Add custom message for inclusion validation to include the allowed values.
* Force user to choose document_type from select lik the one shown at verification form.
* Convert stored document_type to a human readable text
We were very inconsistent regarding these rules.
Personally I prefer no empty lines around blocks, clases, etc... as
recommended by the Ruby style guide [1], and they're the default values
in rubocop, so those are the settings I'm applying.
The exception is the `private` access modifier, since we were leaving
empty lines around it most of the time. That's the default rubocop rule
as well. Personally I don't have a strong preference about this one.
[1] https://rubystyle.guide/#empty-lines-around-bodies
This model without database allow us to validate incoming file extension and
headers and also does the following during importation process:
* Ignore empty rows
* Classifiy rows in two groups: created_records, invalid_records
