`list_canvas()` currently does not support pagination

[andrewbatallones]

Hey, I have been using this gem and with their docs and I need to be able to get canvas that are n pages deep. I see currently the gem does not support pagination and proposed this code change on https://github.com/jonallured/appboy/blob/master/lib/appboy/rest/list_canvas.rb

module Appboy
  module REST
    class ListCanvas < Base
      attr_reader :app_group_id, :sort_direction, :include_archived, :page

      def initialize(app_group_id, options = {})
        @app_group_id = app_group_id
        @sort_direction = options[:sort_direction]
        @include_archived = options[:include_archived]
        @page = options[:page]
      end

      def perform
        http.get '/canvas/list', {
          app_group_id: app_group_id,
          sort_direction: sort_direction,
          include_archived: include_archived,
          page: page
        }.compact
      end
    end
  end
end