Redmine

I tried to use this ruby script to talk to my redmine installation REST API:

require 'rubygems'
require 'active_resource'

class User < ActiveResource::Base
  self.site = 'https://myredmine.com/'
  self.user = 'admin'
  self.password = 'xxxxxxxxxx'
  self.format = :xml
end

puts User.all

The script is working, but it's returning a limit set of my users. I've something like 400 users, only 25 are returned.

How do i do to retrieve all users?