docs: Added misc comments

app/db/session.py

@@ -2,6 +2,7 @@ from typing import AsyncGenerator
 from sqlalchemy.ext.asyncio import create_async_engine, async_sessionmaker, AsyncSession
 from app.core.config import settings
 
+# Create async database engine
 engine = create_async_engine(
     settings.DATABASE_URL,
     echo=False,
@@ -10,6 +11,7 @@ engine = create_async_engine(
     max_overflow=20,
 )
 
+# Async session factory
 AsyncSessionLocal = async_sessionmaker(
     bind=engine,
     class_=AsyncSession,
@@ -18,6 +20,7 @@ AsyncSessionLocal = async_sessionmaker(
 
 
 async def get_db() -> AsyncGenerator[AsyncSession, None]:
+    """Dependency for obtaining an asynchronous database session"""
     async with AsyncSessionLocal() as session:
         try:
             yield session