Chat rooms are created by repository

[gogl92]

As a user I want a chat room to be created for every repository I open.

Acceptance Criteria

• Create a room chat in the database.
• Store: repository name, link, visibility (public, private).
• Link all conversations to this chat room if the users are in the same repository.
• If the repository chat room already exists do not create a new one, prompt the user to the repository chat room.