ASP.NET Core RBAC Module Development

I need a self-contained Role-Based Access Control module that plugs straight into an existing ASP.NET Core application built on Identity. The module must let me create roles (Admin, Manager, User by default),... (Budget: £10 - £20 GBP, Jobs: .NET, .NET Core, API Development, ASP.NET, C# Programming, Documentation, Microsoft SQL Server, Security)