Combined uniqueness validator
Add the following line to your Gemfile
Validate combined uniqueness of any number of fields:
validate_combined_uniqueness_of :first_field, :second_field, :third_field
It is like creating a primary key on these fields but logically (this means validations will be performed by `ActiveModel`, not by your database).
Andrea Schiavini (github.com/metalelf0)
Contributing to combined_uniqueness_validator
do what you want with it :) If you want to report issues, fork it, send pull requests… you're welcome ;)