Rake task for manually running validations across all models and records

[kevinrobinson]

In the work for #2156, it came up that there are models in the database that violation validations. This can happen when we add a validation, ship it, and then don't load that model into memory. This is one reason why database constraints are stronger than validations (if violated, they'll raise when adding the constraint).

Work in #2160 should help with adding more constraints, but this adds a one-off task for running all validations on all models and records. I'll run this now to verify there are no other gaps, and potentially schedule it to run and raise weekly if anything gets through. This task will probably be quite slow (Rails presence validations for associations trigger queries to verify that the record is present, even if a database foreign key constraint is present). We could speed this up by ensuring we have foreign key constraints (which immigrant enforces) and changing Rails presence validations on the association to just be presence validations on the key column, or by replacing uniqueness validations with database constraints, but let's see how long this takes first and if we can just run it weekly.

[kevinrobinson]

selfie