thoughtbot/hound — pull request #510 by bernerdschaefer (2014-12-10 19:12:01+00:00)
Title: Only run a single repo_sync job at a time

It's currently possible trigger multiple calls to `/repo_syncs`
from the UI, by clicking the refresh link multiple times, or
reloading the page near the start of a sync.

This change ensures that `/repo_syncs` will not enqueue multiple
synchronization jobs at a time.