Wire up db_password

compose.yml

@@ -10,10 +10,13 @@ services:
       test: ["CMD", "pg_isready", "-U", "postgres"]
     volumes:
       - postgres:/var/lib/postgresql/data
+    secrets:
+      - db_password
     environment:
-      - POSTGRES_PASSWORD=${DB_PASS}
-      - POSTGRES_USER=${DB_USER}
       - POSTGRES_DB=${DB_NAME}
+      - POSTGRES_PASSWORD=${DB_PASS}
+      - POSTGRES_PASSWORD_FILE=/run/secrets/db_password
+      - POSTGRES_USER=${DB_USER}
 
   redis:
     image: redis:6.0-alpine