Improved and documented GENERIC_PACK feature

#1077

examples/docker-compose-curseforge.yml

@@ -2,12 +2,12 @@ version: '3.8'
 
 services:
   mc:
-    image: itzg/minecraft-server:java8
+    image: itzg/minecraft-server:${IMAGE_TAG:-java8}
     volumes:
     - ./modpacks:/modpacks:ro
     environment:
       EULA: "true"
       TYPE: CURSEFORGE
-      CF_SERVER_MOD: /modpacks/SkyFactory_4_Server_4.1.0.zip
+      CF_SERVER_MOD: /modpacks/${MODPACK:-SkyFactory_4_Server_4.1.0.zip}
     ports:
-      - 25565:25565
+      - "25565:25565"

examples/docker-compose-generic-pack.yml

@@ -0,0 +1,20 @@
+version: '3.8'
+
+services:
+  mc:
+    image: itzg/minecraft-server:${IMAGE_TAG:-latest}
+    volumes:
+    - data:/data
+    - ./modpacks:/modpacks:ro
+    environment:
+      EULA: "true"
+      TYPE: FORGE
+      DEBUG: "${DEBUG:-false}"
+      VERSION: ${VERSION:-1.17.1}
+      FORGEVERSION: ${FORGEVERSION:-37.0.90}
+      GENERIC_PACK: /modpacks/${MODPACK:-Server-Files-0.0.21.zip}
+    ports:
+      - "25565:25565"
+
+volumes:
+  data: {}