Endless loop with redis-pool

Gemfile

source 'https://rubygems.org'
gem 'redis-pool'
gem 'celluloid-redis'
gem 'ohm'

pool.rb

require 'bundler/setup'
ENV['REDIS_URL'] = "unix:///path/to/redis.sock"
require 'celluloid/redis'
require 'redis/connection/celluloid'
require 'redis/pool'
require 'ohm'

POOL = Redis::Pool.new(size:5, db: 2)
Redis.current = POOL
module Ffl
  module Model
    class Post < Ohm::Model
      def self.db
        Redis.current
      end
      attribute :title
      attribute :heading
      attribute :body
      attribute :etag
      counter   :hits

      unique :title

    end
  end
end

20.times do |i| Ffl::Model::Post.create(title: "Titel #{i}", heading: "Überschrift #{i}", body: "Text #{i}") end