Message.create(content:"hello",send_user:5,recieve_user:6,create_time:DateTime.now,readed:false)
 user.send_messages.find_by(send_user:user.id)[:recieve_user]
 user.send_messages.select("recieve_user").
 user.send_messages.select(:recieve_user).find(1).recieve_user

 Message.where(send_user:5,recieve_user:6)


Message.where(send_user:[6,8],recieve_user:[6,8]).select(:send_user,:recieve_user)
user.recieve_messages.where(readed: false).count