docker: facilitate multiple instances in same host

start using namespace because more things are going to come in same
docker compose

.env.example

@@ -1,8 +1,8 @@
-DOMAIN=localhost
+DH_DOMAIN=localhost
+DH_PORT=8000
 DEMO=true
 # note that with DEBUG=true, logs are more verbose (include tracebacks)
 DEBUG=true
-ALLOWED_HOSTS=${DOMAIN},${DOMAIN}:8000,127.0.0.1,127.0.0.1:8000
 DPP=false
 
 STATIC_ROOT=/tmp/static/
@@ -16,6 +16,7 @@ EMAIL_BACKEND="django.core.mail.backends.smtp.EmailBackend"
 EMAIL_FILE_PATH="/tmp/app-messages"
 ENABLE_EMAIL=false
 PREDEFINED_TOKEN='5018dd65-9abd-4a62-8896-80f34ac66150'
+DH_ALLOWED_HOSTS=${DH_DOMAIN},${DH_DOMAIN}:${DH_PORT},127.0.0.1,127.0.0.1:${DH_PORT}
 # TODO review these vars
 #SNAPSHOTS_DIR=/path/to/TODO
 #EVIDENCES_DIR=/path/to/TODO

docker-compose.yml

@@ -5,13 +5,14 @@ services:
       dockerfile: docker/devicehub-django.Dockerfile
     environment:
       - DEBUG=${DEBUG:-false}
-      - DOMAIN=${DOMAIN:-localhost}
-      - ALLOWED_HOSTS=${ALLOWED_HOSTS:-$DOMAIN}
+      - DOMAIN=${DH_DOMAIN:-localhost}
+      - PORT=${DH_PORT:-8000}
+      - ALLOWED_HOSTS=${DH_ALLOWED_HOSTS:-$DH_DOMAIN}
       - DEMO=${DEMO:-false}
       - PREDEFINED_TOKEN=${PREDEFINED_TOKEN:-}
       - DPP=${DPP:-false}
     volumes:
       - .:/opt/devicehub-django
     ports:
-      - 8000:8000
+      - ${DH_PORT}:${DH_PORT}