user guide with image 💪

Author: Yihe-Harry

docs/README.md

@@ -1,5 +1,11 @@
 # User Guide for Duke Memo
 
+![duke1](https://user-images.githubusercontent.com/67280376/108384335-9f8c1600-7245-11eb-8b6a-990e3830b0fc.png)
+
+![duke2](https://user-images.githubusercontent.com/67280376/108384416-b16db900-7245-11eb-8769-92e7f3970c8c.png)
+
+![duke3](https://user-images.githubusercontent.com/67280376/108384424-b3377c80-7245-11eb-8d43-f66288539e9f.png)
+
 ## Features 
 
 1. add tasks