Handle username and XUID for ALLOW_LIST_USERS (#367)

Author: chrisw-dev

README.md

@@ -151,10 +151,12 @@ There are two ways to handle a whitelist:
 
 The first is to set the `ALLOW_LIST` environment variable to true and map in an [allowlist.json](https://minecraft.wiki/w/Whitelist.json) file (previously known as "whitelist.json") that is custom-crafted to the container. 
 
-The other is to set the `ALLOW_LIST_USERS` environment variable to a comma-separated list of gamer tag usernames that should be allowed. The server will look up the names and add in the XUID to match the player.
+The other is to set the `ALLOW_LIST_USERS` environment variable to a comma-separated list of gamer tag usernames and their corresponding XUIDs. Each username should be followed by its XUID, separated by a colon. The server will use these details to match the player.
+
+There are various tools to look XUIDs up online and they are also printed to the log when a player joins the server.
 
 ```shell
--e ALLOW_LIST_USERS="player1,player2,player3"
+-e ALLOW_LIST_USERS="player1:1234567890,player2:0987654321"
 ```
 
 ## Mods Addons 

bedrock-entry.sh

@@ -167,7 +167,11 @@ if [[ -n "$ALLOW_LIST_USERS" || -n "$WHITE_LIST_USERS" ]]; then
 
   if [[ "$allowListUsers" ]]; then
     echo "Setting allow list"
-    jq -c -n --arg users "$allowListUsers" '$users | split(",") | map({"ignoresPlayerLimit":false,"name": .})' > "allowlist.json"
+    if [[ "$allowListUsers" != *":"* ]]; then
+      jq -c -n --arg users "$allowListUsers" '$users | split(",") | map({"ignoresPlayerLimit":false,"name": .})' > "allowlist.json"
+    else
+      jq -c -n --arg users "$allowListUsers" '$users | split(",") | map(split(":") | {"ignoresPlayerLimit":false,"name": .[0], "xuid": .[1]})' > "allowlist.json"
+    fi
     # activate server property to enable list usage
     ALLOW_LIST=true
   else