feat: add Copilot instructions for VerticalSliceArchitecture

Author: nadirbad

.github/copilot-instructions.md

@@ -0,0 +1,54 @@
+# Copilot instructions for VerticalSliceArchitecture
+
+Use these project-specific guidelines to propose changes and generate code that fits this repo.
+
+## Big picture
+
+- Solution has 2 projects:
+  - `src/Api` (ASP.NET Core entrypoint hosting DI, middleware, Swagger). Controllers live in the Application project.
+  - `src/Application` (all features, domain, infrastructure, and shared concerns). Code is organized by vertical slices under `Features/**`.
+- Each feature keeps the HTTP endpoint, request/response types, validation, and MediatR handler together in one file. Example: `Features/TodoItems/CreateTodoItem.cs` contains:
+  - `CreateTodoItemController : ApiControllerBase` with explicit route attribute
+  - `record CreateTodoItemCommand : IRequest<ErrorOr<int>>`
+  - `AbstractValidator<CreateTodoItemCommand>` (FluentValidation)
+  - `IRequestHandler<,>` that uses `ApplicationDbContext`
+- Cross-cutting behaviors are provided via MediatR pipeline: `AuthorizationBehaviour`, `PerformanceBehaviour`, `ValidationBehaviour`.
+- Persistence via EF Core in `Infrastructure/Persistence/ApplicationDbContext.cs`. Domain events are collected and dispatched after `SaveChangesAsync`.
+- Default DB is in-memory; set `UseInMemoryDatabase=false` and configure `DefaultConnection` in `src/Api/appsettings.json` to use SQL Server.
+
+## Conventions and patterns
+
+- Add new endpoints under `src/Application/Features/<Feature>/<Action>.cs`. Keep controller, command/query, validator, handler, and DTOs together unless the file becomes unwieldy.
+- Controllers should inherit `ApiControllerBase` and typically use explicit absolute routes, e.g. `[HttpPost("/api/todo-items")]` or `[HttpGet("/api/todo-lists")]` (see existing features).
+- Handlers access data via `ApplicationDbContext` directly; no repository abstraction. Prefer `AsNoTracking()` for queries.
+- Return types use ErrorOr: commands return `ErrorOr<T>`, queries return `ErrorOr<VM>` and map entities to read models/records in the same file.
+- Add validators with `includeInternalTypes: true` (already wired). Validation errors flow via `ErrorOr` and `ApiControllerBase.Problem`.
+- Use domain events from entities (e.g., add `TodoItemCreatedEvent` to `entity.DomainEvents`). Handlers for domain events live under `Features/.../EventHandlers`.
+
+## Key files
+
+- `src/Api/Program.cs` – DI, middleware (Swagger, CORS any-origin, ProblemDetails), health checks.
+- `src/Application/ConfigureServices.cs` – registers MediatR + pipeline behaviors + validators; configures EF Core (in-memory or SQL Server).
+- `src/Application/Common/ApiControllerBase.cs` – Mediator access and consistent error handling using ErrorOr.
+- `src/Application/Infrastructure/Persistence/ApplicationDbContext.cs` – DbSets, auditing, domain event dispatch.
+
+## Developer workflows
+
+- Build: `dotnet build` (or VS Code task "build").
+- Run API: `dotnet run --project src/Api/Api.csproj` (or task "watch"). Swagger UI is at `/`.
+- Tests: `dotnet test tests/Application.UnitTests/Application.UnitTests.csproj`; integration tests require a SQL instance.
+- EF Core migrations (from repo root):
+  - Add: `dotnet ef migrations add <Name> --project src/Application --startup-project src/Api --output-dir Infrastructure/Persistence/Migrations`
+  - Update DB: `dotnet ef database update --project src/Application --startup-project src/Api`
+- Formatting/analysis: `dotnet format` (or `--verify-no-changes`).
+
+## Integration points
+
+- Packages: MediatR, FluentValidation, ErrorOr, EF Core, Swashbuckle (Swagger).
+- Sample REST requests are under `requests/**` for quick manual testing.
+
+## When adding a new feature
+
+- Create a single file under `Features/<Area>/<VerbNoun>.cs` that mirrors the existing Todo examples.
+- Use explicit routes, ErrorOr results, validators, and `ApplicationDbContext`. Add domain events if applicable.
+- Keep controllers thin; push logic into the handler, and map entities to DTOs/VMs in the same file.

README.md

@@ -1,5 +1,7 @@
 # Vertical Slice Architecture example in .NET 9
 
+![CodeRabbit Pull Request Reviews](https://img.shields.io/coderabbit/prs/github/nadirbad/VerticalSliceArchitecture?utm_source=oss&utm_medium=github&utm_campaign=nadirbad%2FVerticalSliceArchitecture&labelColor=171717&color=FF570A&link=https%3A%2F%2Fcoderabbit.ai&label=CodeRabbit+Reviews)
+
 Check out my blog post [A Guide to Vertical Slice Architecture in C# .NET](https://nadirbad.dev/posts/vetical-slice-architecture-dotnet/) for more details about Vertical Slice Architecture.
 
 This project is an experiment trying to create an API solution template that uses a Vertical Slice architecture style.
@@ -9,7 +11,7 @@ Vertical Slice architecture can be a starting point and can be evolved later whe
 
 > We can start simple (Transaction Script) and simply refactor to the patterns that emerges from code smells we see in the business logic. [Vertical slice architecture by Jimmy Bogard](https://jimmybogard.com/vertical-slice-architecture/).
 
-# Give it a star ⭐
+## Give it a star ⭐
 
 Loving it? Show your support by giving this project a star!