[MyMeta]: Create instances of the backend services for individual pull requests

[dysbulic]

Currently, the only way to test changes to the backend are to merge them into develop and use test.metagame.wtf. For frontend changes, an individual instance is created in Vercel for each pull request. We would like that functionality optionally for the backend.

The backend is currently deployed to render.com where production and staging instances are running.

A significant portion of our requests are frontend only, so do not really need this functionality.

Ideally, this would be an optional step where a user could run a command and change the Vercel test instance for a pull request from running against the staging backend to running against an a custom instance with that request's code. Or, at least, choose whether or not to use the staging backend when creating the pull request.

The instances should also be automatically destroyed when the pull request is merged to develop.

My slight concern is cost. The backend consists of Hasura, Express, and Postgres instances. The cost per server per month is $7 on Render ($21 per site). At any given time there are, perhaps, 15 pull requests open (though half of those are generally dependabot). An additional, say, seven instances running would significantly increase maintenance costs.

I'd really like to be able to put a number to the cost per month of having backend testing instances.

I have repeatedly looked into Kubernetes hoping to use Google's free tier as much as possible to reduce costs. Unfortunately, the learning curve for K8s is pretty steep and I've not yet been able to deploy everything.

@Blairv started the process of creating the test servers using Docker Swarm to avoid the complexity of K8s, but after one pairing session we have not pursued it further. In fairness, my interest in Docker Swarm isn't as great as Kubernetes, which I keep hearing about.