public function attachRoleBySlug($slug)
    {
        $role = Role::where('slug', $slug)->first();

        return $this->attachRole($role);
    }
public function attachRoleBySlug($slug)
    {
        $role = Role::where('slug', $slug)->first();

        return $this->attachRole($role);
    }
public function attachRoleBySlug ( $ slug ) { $ role = Role :: where ( 'slug' , $ slug ) -> first ( ) ; return $ this -> attachRole ( $ role ) ; }
Attach a role to user using slug.

@param $slug
@return bool
Attach a role to user using slug .