Ensuring we don't break user systems

[Julien Lepiller]

Hi guix!

I recently had an idea about how we should organize ourworkflow for post 1.0. 
The goal is to ensure that users can always update their system.

Currently, we push updatesto master and they may not build on other 
architectures or break dependant packages. This is bad because a security 
update might get blocked because an unrelated package now fails to build.

I'd like to propose the following policy:

We wouldcreate a new branch, stable, that would be used by guix pull. We would 
continue to push to master or other branches.

Once hydra finds it can build at least as many packages in master than stable, 
it would make master the new stable, hopefully once a day or so.

Security updates would be provided to users by a seéarate channel, to ensure 
important updates are delivered immediately to users.

Another possibility is to use a patch management system like gerrit with a 
similar policy.

WDYT?