Support for register using a seed host (#51)

src/register.ts

@@ -1,4 +1,5 @@
 import registrar from "./registrar";
+import readConfig from "./config";
 import { URLBuilder } from "./url_builder";
 
 const params = process.argv.slice(2);
@@ -9,7 +10,10 @@ if (params.length != 1) {
 }
 
 const bonobUrl = new URLBuilder(params[0]!);
-registrar(bonobUrl)()
+
+const config = readConfig();
+
+registrar(bonobUrl, config.sonos.discovery)()
   .then((success) => {
     if (success) {
       console.log(`Successfully registered bonob @ ${bonobUrl} with sonos`);