Fork channel

Create a new channel as a copy of main.

Rename channel

Rename main to:

Delete channel

Delete main? This cannot be undone.

upgrade-26.sql
create table JobsetRenames (
    project       text not null,
    from_         text not null,
    to_           text not null,
    primary key   (project, from_),
    foreign key   (project) references Projects(name) on delete cascade on update cascade,
    foreign key   (project, to_) references Jobsets(project, name) on delete cascade on update cascade
);