Upgrade ruby models

[gayle]

Take Rails 2 models and make them Rails 4 models that use the same database tables.

[x] age_group
[x] audit_trail
[x] participant
[x] year
[x] family
[ ] role
[ ] user
[ ] contact - this model stores data that was entered on the contact form. I'm not sure why this is an active record model, and I don't think we need to persist that data. The contact form should just be there to send an email to someone. May need to write a migration to remove this table.
[ ] contact_mailer

And helpers
[ ] ApplicationHelper
[ ] others?