Make Docker preview host ports configurable

Author: MGRAFF2006

docker-compose.yml

@@ -17,7 +17,7 @@ services:
   hub:
     build: ./sorrel-hub
     ports:
-      - "3000:3000"
+      - "${SORREL_HUB_PORT:-3000}:3000"
     environment:
       HOST: "0.0.0.0"
       PORT: "3000"
@@ -35,7 +35,7 @@ services:
   hub-web:
     build: ./sorrel-hub-web
     ports:
-      - "5180:5180"
+      - "${SORREL_HUB_WEB_PORT:-5180}:5180"
     environment:
       HOST: "0.0.0.0"
       PORT: "5180"
@@ -47,7 +47,7 @@ services:
   web:
     build: ./sorrel-web
     ports:
-      - "4173:80"
+      - "${SORREL_WEB_PORT:-4173}:80"
 
 volumes:
   hub-data:

docs/GETTING_STARTED.md

@@ -84,6 +84,9 @@ parked on a normal `git/<branch>` lane for explicit merge resolution.
 docker compose up --build
 ```
 
+If a preview port is occupied, override it with `SORREL_HUB_PORT`,
+`SORREL_HUB_WEB_PORT`, or `SORREL_WEB_PORT` before running Compose.
+
 | Service | URL |
 | --- | --- |
 | Hub API | http://localhost:3000 |