feat: add foreign key constraints and metrics for blockchain node

apps/pool-hub/src/poolhub/__init__.py

@@ -0,0 +1,13 @@
+"""AITBC Pool Hub service package."""
+
+from .settings import Settings, settings
+from .database import create_engine, get_session
+from .redis_cache import get_redis
+
+__all__ = [
+    "Settings",
+    "settings",
+    "create_engine",
+    "get_session",
+    "get_redis",
+]