make find_or_create_by methods work right with validations

gistfile1.rb

  # This and the next method are unfortunately 'magic'
  # They set default paramaters for these two find_or_create_by_ method_missing methods
  def self.find_or_create_by_email(params)
    params = { email: params } unless params.is_a?(Hash)
    super(params.reverse_merge(
      password: Digest::MD5.hexdigest("#{rand(1024)}Time.now"),
      username: Digest::MD5.hexdigest("#{rand(1024)}Time.now")
    ))
  end
  
  def self.find_or_create_by_username(params)
    params = { username: params } unless params.is_a?(Hash)
    super(params.reverse_merge(
      email: Digest::MD5.hexdigest("#{rand(1024)}Time.now") + "@example.com",
      password: Digest::MD5.hexdigest("#{rand(1024)}Time.now")
    ))
  end