Reference : Attribute types : Roles
  
Roles
Members can use the roles attribute to have several roles in addition to their inherited role. The roles attribute can be added to Members only, and can be used only once.
If you use the roles attribute, you can access views based on these settings:
the “Inherit From” attribute that is specified in the Members module
the settings that are defined for the other roles.
Consider a scenario where there are five roles represented by five folders in the Members module: Product Manager, Team Leader, Project Manager, Developer, and Tester. Users are grouped according to the roles. Each user gains access by inheriting views from the role that they belong to.
If you want to allow a user with the Developer role to access the views that are defined for the Tester role, you can add the roles attribute to the Members module, edit the attribute for the Developer, and create a link to the Tester role (folder).
 
Setting
Description
Type
The type for a roles attribute is always a link.
Allowed Target
By default, the allowed target is Members module. As the only module in which Roles attribute can be used is Members, it cannot be edited. Target can also be set to a view on the Members module.
Link Color
Select the color of the links that connect the elements in the Gantt chart, and the Relational graph. This setting do not affect other links.
Log Changes
If this check box is selected, history logs are created for each change of the attribute value.
See also
Attribute types