Is there support for multiple environnements? (stage deployment with dev, integration, pre-prod, prod for instance) Or do I have to create multiple projects?

https://www.graph.cool/docs/reference/graphcool-cli/commands-aiteerae6l Take a look to CLI docs

I have a related question: how do you create a new target?

I had read that, but I now got my answer from the other link above: “Note that in case your .graphcoolrc did not yet contain a target called prod, a new target with that name will be created.”