Added support to re-register to add a discord uuid

+ With plugin support, users can be created without discord uuids
+ When a player wants to use geoffrey in discord, they just need to register in discord

GeoffreyApp/api/commands.py

@@ -151,7 +151,13 @@ def register(player_name, discord_uuid):
     mc_uuid = grab_UUID(player_name)
 
     try:
-        get_player(mc_uuid=mc_uuid)
+        player = get_player(mc_uuid=mc_uuid)
+
+        if len(discord_uuid) != 0 and len(player.discord_uuid) == 0:
+            player.discord_uuid = discord_uuid
+            player.save()
+            return player
+        else:
             raise PlayerInDBError
     except PlayerNotFound:
         player = Player.objects.create(name=player_name, mc_uuid=mc_uuid, discord_uuid=discord_uuid)