Update README.md

README.md

 # vk_u2f_gradle
 add gradle plugin into fido u2f applet from [vk_u2f](https://github.com/VivoKey/vk-u2f)
+
+## applet install
+1. download vku2f
+2. use intelliJ to open the project
+3. build javacard
+4. install applet by cmd
+    1. open cmd by admin
+    1. change directory to the location of cap file
+    1. gp --install applet.cap
+5. put certificate
+    1. copy the command in the cert.txt
+    1. run the command