message: fix lecture/unit import
diff: @@ -79,7 +79,7 @@ lectureSchema.methods.import = function(courseId: String) {
  const lectureId = savedLecture._id;
  return Promise.all(units.map((unit) => {
  - return new Unit(unit).import(courseId, lectureId);
  + return new Unit(unit).import(courseId);
  }))
  .then((importedUnits) => {
  savedLecture.lectures.concat(importedUnits);
  