fixed course archive generation

python/educational-core/src/com/jetbrains/edu/coursecreator/CCUtils.java

@@ -307,7 +307,7 @@ public class CCUtils {
     });
     if (task.getTestsText().isEmpty()) return null;
     lesson.addTask(task);
-    lesson.setIndex(1);
+    lesson.setIndex(course.getLessons().size());
     return lesson;
   }
 }

python/educational-core/src/com/jetbrains/edu/coursecreator/CCVirtualFileListener.java

@@ -68,7 +68,7 @@ public class CCVirtualFileListener implements VirtualFileListener {
       return;
     }
 
-    task.addTaskFile(taskRelativePath, 1);
+    task.addTaskFile(taskRelativePath, task.getTaskFiles().size()+1);
   }
 
   @Override

python/educational-core/src/com/jetbrains/edu/coursecreator/actions/CCCreateCourseArchive.java

@@ -97,6 +97,7 @@ public class CCCreateCourseArchive extends DumbAwareAction {
         archiveFolder.refresh(false, true);
         Course courseCopy = course.copy();
         replaceAnswerFilesWithTaskFiles(courseCopy);
+        courseCopy.sortLessons();
         additionalFiles(courseCopy);
         generateJson(archiveFolder, courseCopy);
         VirtualFileManager.getInstance().refreshWithoutFileWatcher(false);

python/educational-core/src/com/jetbrains/edu/learning/courseFormat/Course.java

@@ -14,6 +14,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.stream.Collectors;
 
@@ -200,6 +201,10 @@ public class Course {
     return false;
   }
 
+  public void sortLessons() {
+    Collections.sort(lessons, EduUtils.INDEX_COMPARATOR);
+  }
+
   @Override
   public String toString() {
     return getName();