Get details from pivot column [Laravel 5]

I have 3 tables: Project, Group, User

and one relation pivot table: project_group with colmuns: id project_id group_id and pivot field user_id

I know how to take all Groups and Projects:

Project::find(1)->groups()->get();

groups() is belongToMany function inside Project Model.

Problem is I don't know how to get all users for particular project. I need to get project and all users names and ids for that project, any solution for this?

Thanks in advance

via Chebli Mohamed