update readme

README.md

@@ -25,6 +25,8 @@ It has the following features:
 - 23-11-2018: Released imagenet-pretrained weights for [resnext50_32x4d](torchreid/models/resnext.py).
 - 11-11-2018: Added multi-dataset training; Added cython code for cuhk03-style evaluation; Wrapped dataloader construction to Image/Video-DataManager; Wrapped argparse to [args.py](args.py); Added [MLFN (CVPR'18)](https://arxiv.org/abs/1803.09132).
 
+Note: Some changes will be discussed in [issues](https://github.com/KaiyangZhou/deep-person-reid/issues).
+
 ## Installation
 1. `cd` to your preferred directory and run `git clone https://github.com/KaiyangZhou/deep-person-reid`.
 2. Install dependencies by `pip install -r requirements.txt` (if necessary).