Modify to add face deteion

Author: wistronitlab

Diff for: README.md

@@ -71,4 +71,7 @@ Keras來解決問題的同好，或是對深度學習有興趣的在學學生可
 
 ### 6.圖像標題 (Image Caption)
 
-### 7.自然語言處理 (Natural Language Processing)
+### 7.人臉偵測辨識 (Face Detection/Recognition)
+* [7.0: 人臉偵測 - OpenCV (Haar特徵分類器)](http://nbviewer.jupyter.org/github/erhwenkuo/deep-learning-with-keras-notebooks/blob/master/7.0-opencv-face-detection.ipynb)
+
+### 8.自然語言處理 (Natural Language Processing)