To do #744
User story #736: As a user I want to see pending effort in Sprint board tasks
Add pending_effort based on custom field to tasks and render it in sprint board
- Added pending_effort based on custom field to tasks and rendered it in sprint board.
- Added setting to select custom field for pending_effort.
- Refactorize sprint board & product backlog to use partials for post-its.
git-svn-id: https://svn.ociotec.com/Software/Web/Redmine/plugins/scrum/trunk@1586 1633e602-76eb-4acd-8a1c-850ebfcfe024