build: use own server that I keep connected

[avelino]

before I had blink build I already used blink to work remotely via mosh, I found the practicality of build very good, however a new machine is configured (droplet at DigitalOcean).

build could support integration with my server, which I already keep on 24 hours a day.

in short: I don't want to use your infrastructure, I want to use my infrastructure

I think it's fair that you charge for the build feature, even though I don't use your server infrastructure (it's my choice not to).

cc @carloscabanero