feat: add database configuration and health check

backend/hermes/app/db/database.py

@@ -0,0 +1,29 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import DeclarativeBase
+from sqlalchemy.orm import sessionmaker
+
+from app.core.config import settings
+
+
+engine = create_engine(
+    settings.database_url,
+    echo=False
+)
+
+SessionLocal = sessionmaker(
+    autocommit=False,
+    autoflush=False,
+    bind=engine
+)
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()