NewRoomChan creates a new room for clients to join.

NewSaveMessageChan create a new SaveMessage channel.

RoomChat take a room, return a HandlerFunc, responsible for send & receive websocket data for all channels.

Channel holds information about one specific channel in the room.

Client represents a user connect to a room, one user may have many devices to chat, so it should not be the same as user.

Message represents a single message which a client sent to a room (same meaning as a user send to a channel).

Room represents a room to chat.

SaveMessage uses to save Message to db.

User hold information about an user.

UserKey is key to save user to context.