def url(perms = :delete, application_type=:desktop, callback_url=nil)
      @frob = get_frob if application_type == :desktop
      params = {'perms' => perms.to_s}
      params['frob'] = @frob if @frob
      params['callbackURL'] = callback_url if callback_url
      @endpoint.url_for(nil,params,'auth')
    end
def url(perms = :delete, application_type=:desktop, callback_url=nil)
      @frob = get_frob if application_type == :desktop
      params = {'perms' => perms.to_s}
      params['frob'] = @frob if @frob
      params['callbackURL'] = callback_url if callback_url
      @endpoint.url_for(nil,params,'auth')
    end
Get the URL to allow the user to authorize the application
 [perms] the permissions you wish to get, either :read, :write, or :delete
 [application_type] if :desktop, a frob is gotten and the URL is suitable for a desktop application.  if :web, a url suitable for the web is returned.
 [callback_url] the callback URL you want the user sent to after they authorize.  This will have the frob and you must call frob= before get_token with the frob that was given to you.