Fixes from review

.env.template

 # host port
-PORT=
+PORT=8080
 # container restart policy
-RESTART=
+RESTART=unless-stopped
+# HTTP folder, will be served at http://localhost:$PORT/data
+# use absolute path or relative path starting with ./
+HTTP_FOLDER=./www

README.md

 ## Mirador Video Annotation POC
 
-Run `docker-compose up -d`, which will serve a mirador instance to `http://localhost:8080`. If sources files are modified, run `docker-compose up -d --build`
+Copy `.env.template` to `.env`, set `$PORT` and check the other configuration variables.  
+Run `docker-compose up -d`, which will serve a mirador instance at `http://localhost:$PORT`. The `$HTTP_FOLDER` directory will be accessible via HTTP at `http://localhost:$PORT/data` and can be used to store manifests and theirs ressources and see them in Mirador.  
+If sources files are modified, run `docker-compose up -d --build` to update Mirador  
+

docker-compose.yml

@@ -6,5 +6,5 @@ services:
     ports:
       - $PORT:80
     volumes:
-      - ./www:/srv/data
+      - $HTTP_FOLDER:/srv/data
       - ./Caddyfile:/etc/caddy/Caddyfile