Update README (#127)

Update README

README.md

@@ -7,14 +7,17 @@ Documentation of the protocol used can be found in [doc/protocol.md](doc/protoco
 - Interactive mode: `java tracker.Tracker`
 - CLI Arguments mode: `java trackerP2P.trackerP2P -- <hostname> <PORT>` (default port 6969 (range 6000 -> 6999))
 
-### Server-only
+### Server-only (only for tests purposes)
 - Interactive mode: `java serveurP2P.ServeurP2P`
 - CLI Arguments mode: `java serveurP2P.ServeurP2P -- <serveurHOSTNAME> <serveurPORT> <trackerHOSTNAME> <trackerPORT>` (default server port: server 7070 (range 7000->7070) and tracker port 6969 (range 7000 -> 7999))
 
-### Client+Server
+### Application CLI (Client+Server)
 - Interactive mode: `java clientP2P.ClientP2P`
 - CLI Arguments mode: `java clientP2P.ClientP2P -- <clientTransportProtocol> <integratedServerHOSTNAME> <integratedServerPORT> <trackerHOSTNAME> <trackerPORT>` (default tracker port 6969 (range 7000 -> 7999) and server port: server 7070 (range 7000->7070))
 
+### Application GUI (Client+Server)
+- `java gui.ClientP2PGUI`
+
 ## Sujet
 Lien vers le [document original](https://stri-online.net/FTLV/mod/resource/view.php?id=1753).