When a user is created in ADMIN section, it should be addable directly as a manager in project users configuration

[gvincke]

User case : i create a user in the admin section. I go to my project, and whant to add it as a manager. Does not work. I must first add it as a contributor (wich he is not) and after add him as a manger or representative. Shorter way : i should have been abale to add him directly as a manager, wich automaticly add him as a contributor if necessary. OR : change label of "Add contributor" in "Add a user" and explain that users will be by default contributor unless explictly setted up as managers.