Added comments

mozen/src/main/java/mozen/business/CommentManager.java

mozen/src/main/java/mozen/business/ICommentManager.java

mozen/src/main/java/mozen/business/LayerManager.java

mozen/src/main/java/mozen/business/ModelManager.java

mozen/src/main/java/mozen/messages/CommentMessage.java

mozen/src/main/java/mozen/model/Comment.java

mozen/src/main/java/mozen/model/Model.java

mozen/src/main/java/mozen/model/User.java

mozen/src/main/java/mozen/repos/CommentRepository.java

mozen/src/main/java/mozen/utils/DatabaseFiller.java

mozen/src/main/java/mozen/utils/UserHelper.java

mozen/src/main/java/mozen/web/CommentController.java

mozen/src/main/java/mozen/web/ModelController.java

mozen/src/main/java/mozen/web/TagController.java

mozen/src/main/java/mozen/web/UserController.java