public function postUserRolePermissions(Request $request)
  {
    $this->validate($request, ['role' => 'required', 'permissions' => 'required']);
    $role = Role::with('permissions')->whereName($request->role)->first();
    $role->permissions()->detach();
    foreach ($request->permissions as $permission_name) {
      $permission = Permission::whereName($permission_name)->first();
      $role->assign($permission);
    }
    \Session::flash('flash_message', 'Permission granted!');
    return \Redirect::route('admin.assign-role-permissions',[
    ]);
  }