Devise with only username no email

There is the wiki of Devise Allow users to sign in using their username or email address

but now we dont need email, only username.

User.rb

attr_accessible :login, :username
attr_accessor :login

def self.find_first_by_auth_conditions(warden_conditions)
	conditions = warden_conditions.dup
	puts "Conditaions: #{conditions}"
	if login = conditions.delete(:login)
	  where(conditions).where(["lower(username) = :value", { :value => login.downcase }]).first
	else
	  where(conditions).first
	end
end

# the 2 methods are very important in Rails 4 and Devise 3.1.0
def email_required?
	false
end

def email_changed?
  false
end

/config/initializers/devise.rb

config.authentication_keys = [ :login ]