As a Project Administrator you can add as many user roles as needed. 

How to add new user roles

1. Click the gear icon in the bottom of the sidebar to go to Project Settings.  
2. Click the sub-section Users. 
3. In the Roles card you see a system generated user role with access to all modules.
4. Click Add Role to add roles with access to specific modules.
5. After having created roles navigate to the user list in the Users card and assign the appropriate roles to different users.

Where: HOME / <project name> / Project Settings / Users