Ruby Koala gem script to invite all members of multiple groups to an event

FbInviteFromGroups.rb

require 'koala'
require 'date'
require 'enumerator'

# create_event permision is needed
access_token ='<access_token>'

groups = ["<group1id>","<group2id>"]

graph = Koala::Facebook::API.new(access_token)

invites = {}

groups.each do |g|

  members = graph.get_connections(g,'members')
  members.each do |m|
    invites[m['id']] = m['name']
  end
end

# Create Event
params = {
    # :picture => picture,
    :name => 'Event name',
    :description => 'Event description',
    :start_time => Date.new(2012,12,31).to_time.to_s,
    :end_time => Date.new(2013,1,01).to_time.to_s
}

event = graph.put_object('me', 'events', params )

invites.keys.enum_for(:each_slice,4).each do |group|
  graph.put_object(event['id'],'invited',:users =>group.join(','))
end