tomykaira/clockwork — pull request #106 by robisenberg (2014-07-01 18:54:17+00:00)
Title: Bugfix: resolves #104 "undefined methodrun_now? for nil:NilClass"

This should fix the issue that @schneider-th was having in #104.

There was a bug where an error would be raised when the database-backed model had `:at` of `""` (i.e. empty string).