新增 #include "app_uart.h"時遇到 No such file directory的錯誤，看來是Library的沒有UART的參考路徑
解法
1. Click Solution下的Project，右鍵 Option
2. select Private Configurations > "Common"
3. Click "Preprocessor"
4. Click "User Include Directories"
5. 新增../../../../../../components/libraries/uart
