Fixed issue with register

GeoffreyApp/api/commands.py

@@ -153,7 +153,7 @@ def register(player_name, discord_uuid=None):
     try:
         player = get_player(mc_uuid=mc_uuid)
 
-        if discord_uuid is not None and player.discord_uuid == "":
+        if discord_uuid is not None and player.discord_uuid is None:
             player.discord_uuid = discord_uuid
             player.save()
             return player.json