gradeimporter/lib.php

<?php

function tool_devcourse_extend_navigation_course($navigation, $course, $coursecontext) {
    $url = new moodle_url('/admin/tool/devcourse/index.php');
    $devcoursenode = navigation_node::create('Development course', $url, navigation_node::TYPE_CUSTOM, 'Dev course', 'devcourse');
    $navigation->add_node($devcoursenode);
}