Add Devcontainer Setup for Local Development

[elalemanyo]

This pull request adds a complete Devcontainer setup to streamline onboarding and ensure a consistent development environment across machines.

[jorgemanrubia]

We don't use devcontainers so I am not sure about this one. What do you think @kevinmcconnell @flavorjones?

[elalemanyo]

Thanks for the feedback @jorgemanrubia!

Totally understand that devcontainers aren’t part of your current workflow. The intention behind this PR isn’t to change how the project is developed or require anyone to use devcontainers, but to provide an optional setup for contributors who want it.

Rails offers devcontainer support as an option, and many people in the Rails community use it to get an application running quickly without having to install or align local dependencies. For open source projects especially, this can lower the barrier to entry for first-time contributors: clone the repo, open it in a compatible editor, and the app is ready to run.

This setup doesn’t affect existing workflows, CI, or production in any way—it’s purely additive. If someone doesn’t use devcontainers, they can simply ignore the files.

From my perspective, this is mainly about improving onboarding and making the project more accessible to the wider Rails community. Of course, I’m happy to adjust or remove it if you feel it doesn’t align with the project’s goals.

Thanks for considering it! 🙂

[northeastprince]

I'm pretty sure Docker and mise is all that's required and then bin/setup takes care of the rest - is there a scenario where those wouldn't be available?

[elalemanyo]

@northeastprince You’re right: with Docker, mise, and bin/setup, the project works well already.

The devcontainer doesn’t replace that flow — it just wraps it in an optional, fully preconfigured environment. For some contributors, especially first-timers, it means “open the repo and start coding” without installing or aligning local tools first. If you already have everything set up, there’s no added benefit and it can be safely ignored.

Since this repo is a great resource for learning, making the first step as easy and frictionless as possible really matters — similar to how Laravel emphasizes “it just works” onboarding — while keeping the existing setup unchanged.