The .gitignore entry for the .specification file blocks the spec file from being added to an including git repository, so the file is never pulled to the deployment server via Capistrano. Figuring this out can waste a bunch of time.
I am thinking this should either be un-done, or should be well-documented as a common "gotcha" for Capistrano/git deployments.
(Ooops - "close" "close the issue," not "close the window." D'oh!)
(fixed a few months ago: bef0477)