Add duck command to upload atr to SD card to README

Author: markjfisher

README.md

@@ -84,6 +84,8 @@ make clean all diskz
 # use custom banner (you must create your own banners)
 make diskz BANNERMODE=E BANNERSIZE=large BANNERNAME=cng BANNERLOAD=32768 
 
+# uploading directly to SD card on FujiNet
+duck --upload dav://[email protected]/dav/autorun-cng-1.0.0.atr dist/autorun-cng-1.0.0.atr -existing overwrite
 ```
 
 ## Core application