[almighty] Gorm cannot recreate soft-deleted WorkItemTypes

[Thomas Mäder]

Hi Folks,

I have just come across the issue 
https://github.com/jinzhu/gorm/issues/759 when trying to create and 
delete work item types for a test. The gist is: gorm can't recreate 
objects that have been soft-deleted. Using "Unscoped()" does not work in 
this instance, since the soft-deleted work items remain in in the 
database and have a dangling foreign key to the work item types. The bug 
has been close, so I don't think there will be a fix for it. I'm writing 
this because I want people to be aware of the issue.
For our concrete example, I am going to follow one of the suggestions 
from the bug:

> 1, Use ThreadName & DeletedAt as combined unique index

When "DeletedAt" is nil, it becomes the same uniqueness condition as we 
have now. The FK on work_items will have to be fixed, as well.

/Thomas