require 'digest/sha1'

class User < ActiveRecord::Base
  validates_presence_of :username, :password
  def self.authenticate(username, password)
    if password
      sha1password = Digest::SHA1.hexdigest(password)
    else
      sha1password = ''
    end
    return find(:first, :conditions => [ "username = '#{username}' AND password = '#{sha1password}'" ])
  end
end