fix empty tasks failure

Author: ShMcK

lib/reducers/tutorial/config-paths.js

@@ -18,6 +18,9 @@ function configTestString(dir, name, config, testPath) {
 }
 function configPaths(dir, name, config, pages) {
     return pages.map(function (page) {
+        if (!page.tasks) {
+            page.tasks = [];
+        }
         page.tasks.map(function (task) {
             task.tests = task.tests.map(function (testPath) {
                 if (typeof testPath === 'string') {

src/reducers/tutorial/config-paths.ts

@@ -25,6 +25,9 @@ export default function configPaths(
   dir: string, name: string, config: Tutorial.Config, pages: CR.Page[]
 ): CR.Page[] {
   return pages.map((page: CR.Page): CR.Page => {
+    if (!page.tasks) {
+      page.tasks = [];
+    }
     page.tasks.map((task: CR.Task): CR.Task => {
       // change testPaths to use absolute URLs
       task.tests = task.tests.map((testPath: string) => {