chore: rename postgres service to db

docker-compose.yml

@@ -1,5 +1,5 @@
 services:
-  postgres:
+  db:
     image: postgres:16.9-alpine
     restart: unless-stopped
     init: true
@@ -9,6 +9,10 @@ services:
       POSTGRES_PASSWORD: ${POSTGRES_PASSWORD:-replace-with-a-local-password}
     volumes:
       - postgres_data:/var/lib/postgresql/data
+    networks:
+      default:
+        aliases:
+          - postgres
     healthcheck:
       test: ["CMD-SHELL", "pg_isready -U $${POSTGRES_USER} -d $${POSTGRES_DB}"]
       interval: 5s
@@ -24,7 +28,7 @@ services:
     restart: unless-stopped
     init: true
     environment:
-      DATABASE_URL: ${DATABASE_URL:-postgresql://theatre_lab:replace-with-a-local-password@postgres:5432/theatre_lab}
+      DATABASE_URL: ${DATABASE_URL:-postgresql://theatre_lab:replace-with-a-local-password@db:5432/theatre_lab}
       DJANGO_SECRET_KEY: ${DJANGO_SECRET_KEY:-replace-with-a-long-random-development-key}
       DJANGO_DEBUG: ${DJANGO_DEBUG:-true}
       DJANGO_ALLOWED_HOSTS: ${DJANGO_ALLOWED_HOSTS:-localhost,127.0.0.1,backend,azionelab.org}
@@ -34,7 +38,7 @@ services:
     ports:
       - "127.0.0.1:8000:8000"
     depends_on:
-      postgres:
+      db:
         condition: service_healthy
     healthcheck:
       test: ["CMD", "python", "-c", "import urllib.request; urllib.request.urlopen('http://localhost:8000/health/', timeout=2)"]