message: API: Fix getRandomUnitFromLecture return type
diff: @@ -144,7 +144,7 @@ export class FixtureUtils {
  return this.getRandom<IUnitModel>(array, hash);
  }
  - public static async getRandomUnitFromLecture(lecture: ILecture, hash?: string): Promise<IUnit> {
  + public static async getRandomUnitFromLecture(lecture: ILecture, hash?: string): Promise<IUnitModel> {
  const unitId = await this.getRandom<IUnit>(lecture.units, hash);
  return Unit.findById(unitId);
  }
  