fix training tab duplication bug
re-order tab logs
soft delete tabs
add deleted_at to tabs table
run migration
Merge pull request #218 from wangqiang1208/bugfixing/tab-soft-delete

tabs soft delete implementation
Merge pull request #217 from wangqiang1208/bugfixing/course-dup

fix training tab duplication bug
Merge branch 'development' of github.com:Coursemology/coursemology.org into Deploy