parameter root install directory

.env.default

@@ -14,3 +14,4 @@ HOST_MAIL=mail
 TZ=Europe/Paris
 BASIC_AUTH=test:$$apr1$$H6uskkkW$$IgXLP6ewTrSuBkTrqE8wj/
 DELUGE_TORRENT_PORT=6881
+ROOT_INSTALL=/srv

posteio/docker-compose.posteio.yml

@@ -5,7 +5,7 @@ services:
     container_name: poste-io
     image: analogic/poste.io
     volumes:
-      - /srv/data/poste.io:/data
+      - ${ROOT_INSTALL}/data/poste.io:/data
     environment:
       - TZ=${TZ}
       - HTTPS=OFF

traefik/docker-compose.traefik.yml

@@ -49,4 +49,4 @@ services:
     restart: unless-stopped
     volumes:
       - /var/run/docker.sock:/var/run/docker.sock:ro
-      - /srv/hosting/traefik/acme.json:/acme.json
+      - ${ROOT_INSTALL}/hosting/traefik/acme.json:/acme.json