Added and updated the remaining javadoc

...idatt2016/v233/SmartMat/repository/AllergyRepository.java

.../idatt2016/v233/SmartMat/repository/RecipeRepository.java

...2016/v233/SmartMat/repository/ShoppingListRepository.java

...33/SmartMat/repository/group/UserGroupAssoRepository.java

...t2016/v233/SmartMat/repository/group/WasteRepository.java

.../v233/SmartMat/repository/product/CategoryRepository.java

...33/SmartMat/repository/product/FridgeProductAssoRepo.java

...6/v233/SmartMat/repository/product/ProductRepository.java

.../v233/SmartMat/repository/user/AchievementRepository.java

...att2016/v233/SmartMat/repository/user/UserRepository.java

.../ntnu/idatt2016/v233/SmartMat/service/AllergyService.java

...a/ntnu/idatt2016/v233/SmartMat/service/RecipeService.java

.../idatt2016/v233/SmartMat/service/ShoppingListService.java

...va/ntnu/idatt2016/v233/SmartMat/service/TokenService.java

...nu/idatt2016/v233/SmartMat/service/WeeklyMenuService.java

.../idatt2016/v233/SmartMat/service/group/FridgeService.java

...u/idatt2016/v233/SmartMat/service/group/GroupService.java

...u/idatt2016/v233/SmartMat/service/group/WasteService.java

...tt2016/v233/SmartMat/service/product/CategoryService.java

...att2016/v233/SmartMat/service/product/ProductService.java