class Email < ActiveRecord::Base
include Sortable
belongs_to :user
validates :user_id, presence: true
validates :email, presence: true, uniqueness: true, email: true
validate :unique_email, if: ->(email) { email.email_changed? }
def email=(value)
write_attribute(:email, value.downcase.strip)
end
def unique_email
self.errors.add(:email, 'has already been taken') if User.exists?(email: self.email)
end
end