I'm starting work on a fork of bors-ng that i'm calling multibors for now. The goal is to support building multiple staging branches at once. If an r+ comes in while nothign is building, we'll build it as normal. If one or more batches are already building, we'll go through all the currently building batches, and create a new batch with the new PR on top. We'll also create a batch with just the newly R+'ed PR.
Then, when a build completes successfully, we'll check if it can be merged without blocking any of the as-yet-incomplete builds that were