# File lib/gravtastic.rb, line 25
  def self.configure(model, *args, &blk)
    options = args.last.is_a?(Hash) ? args.pop : {}

    model.gravatar_defaults = {
      :rating =>   'PG',
      :secure =>   true,
      :filetype => :png
    }.merge(options)

    # The method where Gravtastic get the users' email from defaults to `#email`.
    model.gravatar_source = args.first || :email
  end