add host arg to app

bin/peerjs

@@ -34,6 +34,11 @@ const opts = require('optimist')
       demand: false,
       description: 'path to SSL certificate'
     },
+    host: {
+      demand: false,
+      description: 'ip',
+      default: '0.0.0.0'
+    },
     port: {
       demand: true,
       alias: 'p',