src/Router.php
public function pushGroup($pattern, $callable)
    {
        $group = new Group($pattern, $callable);

        array_push($this->routeGroups, $group);

        return $group;
    }
public function pushGroup($pattern, $callable)
    {
        $group = new Group($pattern, $callable);

        array_push($this->routeGroups, $group);

        return $group;
    }
Add a route group to the array

@param string   $pattern
@param callable $callable

@return GroupInterface