fix(db): update async engine configuration to use connection pool settings

db/session.py

@@ -1,6 +1,5 @@
 from sqlmodel import SQLModel
 from sqlalchemy.ext.asyncio import create_async_engine
-from sqlalchemy.pool import NullPool
 from sqlmodel.ext.asyncio.session import AsyncSession
 from core.config import get_settings
 
@@ -10,8 +9,10 @@ async_engine = create_async_engine(
     settings.DATABASE_URL,
     echo=False,
     future=True,
-    poolclass=NullPool,
-    connect_args={"statement_cache_size": 0}
+    pool_pre_ping=True,
+    pool_size=10,  # The number of connections to keep open in the pool
+    max_overflow=5, # The number of connections to allow in "overflow"
+    pool_timeout=30, # How long to wait for a connection from the pool
 )
 
 async def get_db():