history saving update
fix migrations renaming
fix deleting checklist on partial issue updating
fix deleting checklist on partial issue updating
create checklists via ajax
Merge branch 'master' into issue_tabs_updates

Conflicts:
	app/views/issue_checklists/done.js.erb
	app/views/issues/_checklist_compact_form.html.erb
add 'tab-item' class to checklist item