API and database models refactoring

models/database/base.py

@@ -0,0 +1,10 @@
+from datetime import datetime
+from sqlalchemy import Column, DateTime
+from app.core.database import Base
+
+class TimestampMixin:
+    """Mixin to add created_at and updated_at timestamps to models"""
+    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+    updated_at = Column(
+        DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False
+    )