Update README

README.md

@@ -1,14 +1,37 @@
 # GSoC 2017 - Jingle File Transfer Demo App
 ## File synchronisation via XMPP.
 
+This application demonstratest the possibilities of Jingle File Transfer via XMPP. xmpp_sync can be used to mirror the contents of one directory across several computers.
+
+### Building
+
+Since some of the code I wrote for Smack is not yet merged, you'll have to build it yourselves.
+
+```
+git clone git@github.com:vanitasvitae/Smack.git
+cd Smack
+git checkout jingle3
+gradle install
+```
+
+Next clone the repository of xmpp_sync.
+```
+cd ..
+git clone git@github.com:vanitasvitae/xmpp_sync.git
+cd xmpp_sync
+gradle build
+```
+
+The resulting executable jar file can be found in `build/libs` afterwards.
+
+### Available options and commands:
+
 xmpp_sync has two modes: Master and Slave mode. A client started in master mode will send files
 out, while clients in slave mode will receive files.
 
 In order to use the program, you need at least two XMPP accounts (which might be on different
 servers). I recommend using a server, which supports Socks5 proxies.
 
-### Available options and commands:
-
 The application has the following options available when being started.
 ```
 usage: client [-d] -D <arg> [-h] [-m] -p <swordfish> -u <user@server.tld>