Offline process messages
The messages that tells the user a task is over are not saved in the message framework but sent directly though the opened websocket. If the user leaves the website the message will be lost. Check whether it's possible to tell if the message was received and if it wasn't add it to django's message framework. If it's not possible we need to find a way to check if the user is connected or not, beware that listing opened sockets is not recommended by channels because it is really inefficient so we may need to store opened connections another way (in redis ?).