fixed dockerfile for backend

# !! Please change your .env files according to the updated notion


https://www.notion.so/uwblueprintexecs/Environment-Variables-11910f3fb1dc80e4bc67d35c3d65d073

Co-authored-by: Emily Nie <[email protected]>

Author: sunbagel

docker-compose.yml

@@ -23,6 +23,8 @@ services:
     depends_on:
       db:
         condition: service_healthy
+    environment:
+      POSTGRES_DATABASE_URL: ${POSTGRES_DATABASE_URL}
   db:
     container_name: llsc_db
     image: postgres:16-alpine