The right way to validate uniqueness case insensitive of email in Ruby on Rails.

Validate Email in RoR

##Check uniqueness of email-----------------------------------------------
#in migration
add_index :users, :email, :unique => true

#but that doesn't cover case insensitive
#in the model take email to lowercase before save

class User..
  attr_accessible :email
  #this gives you custom message for the error
  validates :email => uniqueness => { :message => "is a duplicate" }
  #this is the callback
  before_validate :normalize_emailß
  
  def normalize_email
    self.email = self.email.downcase.strip
  end
  
  #an even better way
  def email=(email)
    super(email.downcase.strip)
  end
  
end