GitPod development environment

[TiagoCavalcante]

GitPod is used in Symja, it allows easily start contributing to any project.

We could add a .gitpod.yml file and "Open in GitPod" button.
GitPod allows us to use a custom Docker image and initialization commands, so we could create a .gitpod.yml easily.

[TiagoCavalcante]

@rocky @mmatera what do you think?

[rocky]

I don't have an opinion, but if you want to try it, go ahead and let's see how it goes.

[TiagoCavalcante]

Linked PR: #114

[rocky]

Does gitpod work on the branch?

[TiagoCavalcante]

It works in my fork, and that is up-to-date with this repo, so merging is not necessary for testing. (there's a link in the PR for testing, with GitPod, a git pull is not even necessary)