[refactor] Extracted ProblemUnmerge interactor from Problem#unmerge! (25m)
[fix] Updated cached attributes on the problem being unmerged (5m)
[fix] Upgraded Rails to 3.2.18 (1m)
[cifix] Stopped trying (and failing) to install the `debugger` gem on Ruby 1.9 (1m)
[skip] Dropped support for Ruby 1.8 (1m)