Allow project level permissions to override group level permissions
Created by: knl
Currently, the permission model for each project has two components: project and group permissions. Then, the system calculates the effective permissions of a user as max(project permissions, group permissions). However, I think this is not intuitive, as reducing the permissions on a project level will make no effect. Hence, the effective permissions should be the ones defined in the project (if exist), or group otherwise. That way, project permissions would override group permission.
As an extension, I propose to add "None" to project level permissions, that would effectively remove any permissions. This way, one can set group permissions and through setting "None" on a user, exclude it from a particular project. (Although, Guest level should work, as it prevents access to the source code).