Update README.md

Author: ploiu

README.md

@@ -1,3 +1,10 @@
 # file-server-ui
 
 A client frontend for [ploiu/file_server](https://github.com/ploiu/file_server), written in java
+
+## Building
+1. make sure you have the server certificate in the same directory as this README, and make sure it's named `file_server_cert.pem`
+2. run `./gradlew jpackage`
+
+## Installing
+the built installer is located in `./build/file-server-installer`. For linux, you will need to write your own .desktop file until I can figure out how to get the jlink plugin to work with automatic start menu installation. For windows, you will need to navigate to `C:\Program Files\ploiu-file-server` and manually add `ploiu-file-server.exe` to the start menu for the same reason.