requiring a single commercial entity like github is a really bad idea. Sure it'll be fine for a few years but when github goes belly up or gets bought and the new CEO cuts all extraneous projects, then you're hosed.
It might or might not be well managed in the years to come. Case in point, Skype. It was "the" tool to use for office communication. Hardly anyone I know uses Skype nowadays.
cough Mozilla cough Slack cough