Messenger

Network chat for messaging.

Currently implemented:

- chat work offline (reading messages received earlier)

- both group and private chats are created

- display the list and the ability to select all customers in the group

- implemented the ability to create, exit, join, rename, delete group and private chats

- display of the online client (with whom correspondence is conducted)

- real-time message notification when the recipient is offline

- sending message history to the user offline - online