In GanttProject you can add some different people to have resources. Each person could have a function and contacts (like e-mail of phone number)
On GanttProject, you could see this information on the tab pane people.
Here see the different type of functions for the persons
Undefined
Project Manager
Developer
Doc Writer
Tester
Graphic Designer
Doc Translator
Packager (.rpm, .tgz ...)
Analysis
Web Designer
No Specific Role
You could manage the different person of the project (Insert a new person, delete a person or edit the settings of the person).
You could do that by right-click on the different cell of the table or directly on the menu human.