* an inactive user shouldn't be able to be a collaborator
* use translated error message
* add active user check when adding a new collaborator via the api
* fix translation text
* added collaborator test
* improvee testcases
* don't fail silently if trying to add a collaborator twice
* fix translation text
* added collaborator test
* improvee testcases
* Added tests to make sure a collaborator cannot be added twice
Lanre Adelowo
Vlad Temian