class ActionController::Parameters

def permit!

Person.new(params) # => #
params.permitted? # => true
params.permit!
Person.new(params) # => ActiveModel::ForbiddenAttributesError
params.permitted? # => false
params = ActionController::Parameters.new(name: "Francesco")

end
class Person < ActiveRecord::Base

mass assignment. Returns +self+.
Sets the +permitted+ attribute to +true+. This can be used to pass 
def permit!
  each_pair do |key, value|
    Array.wrap(value).flatten.each do |v|
      v.permit! if v.respond_to? :permit!
    end
  end
  @permitted = true
  self
end