little of backend

backend/app/db/database.py

@@ -0,0 +1,19 @@
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+import os
+
+POSTGRES_USER = os.environ.get("POSTGRES_USER", "user")
+POSTGRES_PASSWORD = os.environ.get("POSTGRES_PASSWORD", "password")
+POSTGRES_DB = os.environ.get("POSTGRES_DB", "db")
+POSTGRES_HOST = os.environ.get("POSTGRES_HOST", "postgres")
+
+
+SQLALCHEMY_DATABASE_URL = (
+    f"postgresql://{POSTGRES_USER}:{POSTGRES_PASSWORD}@{POSTGRES_HOST}/{POSTGRES_DB}"
+)
+
+engine = create_engine(SQLALCHEMY_DATABASE_URL)
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+Base = declarative_base()