Update backend documentation

docs/source/overview/server.md

@@ -54,22 +54,28 @@ In this way, for example, an entire competition with it's teams, codes, slides a
 
 ## Active competitions
 
-Slides, timers and answers needs to be synced during an active presentation.
+Slides and timers (and answers) needs to be synced during an active presentation.
 This is done using SocketIO together with flask_socketio.
-Events sent is also authorized via json web tokens.
+Events sent is also authorized via JWT, basically the same way as the for the API calls.
+But for socket events, the decorator that is used to authenticate them is `@authorize_user()`.
 Whenever client joins a competition they will connect via sockets.
-Only a single instance of a competition can be active at a time.
+A single competition cannot be active more than once at the same time.
+This means that you will need to make a copy of a competition if you want to run multiple times at the same time.
 All of the functionality related to an active competition and sockets can be found in the file `app/core/sockets.py`.
+The terms `active competition` and `presentation` means the same thing.
 
 ### Starting and joing presentations
 
-Whenever a client types in a code in the client, the code will be checked via the `api/auth/login/code` API call.
-If there is such a code and it was an operator code, the client will receive a JWT it will need to use to authenticate itself for there on out.
-It will also emit the `start_presentation` event to start the presentation.
+Whenever a client types in a code in the client it will be checked via the `api/auth/login/code` API call.
+If there is such a code and it was an operator code, the client will receive a JWT it will need to use to authenticate itself.
 If there is such a code and the associated competition is active, the client will also receive a JWT, regardless if it was an operator code or not.
-In this case the client will instead emit the `join_presentation` event.
+Both of these cases will be handled by the default `connect` event, using the JWT received from the API call.
+The server can see what is stored in the JWT and do different things depending on it's contents.
 
 ### Syncing between clients
 
-The operator will emit `set_slide` and `set_timer` events that syncs their slides and timers between all clients connected to the same presentation.
-The operator can also emit `end_presentation` to end the current presentation, which will disconnect all connected clients.
+The operator will emit the `sync` event and provide either slide or timer to update it on the server.
+The server will then send `sync` to all connected clients with the updated values, regardless of what was actually updated.
+The server will also store the timer and active slide in order to `sync` clients when they join.
+The operator can also emit `end_presentation` to disconnect all clients from it's competitions.
+This will also end the presentation.