Add initial project

backend/repositories/user_repository.py

@@ -0,0 +1,17 @@
+"""User repository for data access operations."""
+from typing import Optional
+from sqlalchemy.orm import Session
+from backend.models.user import User
+from backend.repositories.base import BaseRepository
+
+
+class UserRepository(BaseRepository[User]):
+    """Repository for User model operations."""
+
+    def __init__(self, db: Session):
+        """Initialize user repository."""
+        super().__init__(User, db)
+
+    def get_by_username(self, username: str) -> Optional[User]:
+        """Get a user by username."""
+        return self.db.query(User).filter(User.username == username).first()