fix(docker): add Dockerfile, .dockerignore, and docker-compose setup

[Srinu346]

fix(docker): Add complete Docker setup for C# CRUD sample app

Problem

The C# CRUD sample application (used to demonstrate Keploy with .NET and PostgreSQL) previously did not include a proper Docker setup.

Fixes: #3787

The existing docker-compose.yml only defined the PostgreSQL service. As a result, users were required to:

1. Install the .NET 8 SDK locally.
2. Run dotnet ef migrations manually.
3. Start the app using dotnet run.
4. Configure environment-specific database connection strings.

This led to:

• Incompatibility with Keploy’s Docker-based recording mode
  (keploy record -c "docker compose up" --container-name crud-app), since the application itself was not containerized.

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Solution

This PR introduces a fully containerized setup, allowing the entire stack (application + database) to run using a single command.

Added / Updated

• Dockerfile
• docker-compose.yml
• .dockerignore

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How to Run

# Start the full stack
docker compose up

# Start with Keploy recording
keploy record -c "docker compose up" --container-name crud-app

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Visual

Screen.Recording.2026-02-14.162904.mp4