Rails Model Validation: i need validates_inclusion_of with case sensitive false?

Here is code which is not working

    class WeekDay < ActiveRecord::Base
           validates_inclusion_of :day, :in => %w(sunday monday tuesday wednesday thursday friday saturday), :case_sensitive => false
    end

Currently i have all of days in db except sunday. I am trying to add "Sunday", and getting errors "is not included in the list".

validates_inclusion_of does not have a case_sensitive argument, so you can create your own validator(if you are using Rails 3):

class DayFormatValidator < ActiveModel::EachValidator
  def validate_each(object, attribute, value)
    unless %w(sunday monday tuesday wednesday thursday friday saturday).include?(value.downcase)
      object.errors[attribute] << (options[:message] || "is not a proper day.") 
    end
  end
end

and save this in your lib directory as:

lib/day_format_validator.rb

Then in your model, you can have:

validates :day, :day_format => true

Just make sure rails loads this lib file on startup by putting this in your config/application.rb:

config.autoload_paths += Dir["#{config.root}/lib/**/"]