Help with entering branch names

[sudara]

• As a user I want help entering branch names so it's less likely that I create a job for a non-existent branches.

[sudara]

get fetch && git branch -a could populate the list every 15 min?

[Manfred]

• Show active branches for the current user
• Allow easy selection from all current branches (auto-complete, search, or just a long list ordered by activity?)

I think we want to use the GitHub API to do this so we can show relevant branches.