Fix some error cases when the number of teams is zero

* There is no config.json
* config.teams.length === 0

src/common/settings.js

@@ -38,5 +38,13 @@ module.exports = {
     }
     var data = JSON.stringify(config, null, '  ');
     fs.writeFileSync(configFile, data, 'utf8');
+  },
+
+  loadDefault: function() {
+    return {
+      teams: [],
+      hideMenuBar: false,
+      version: version
+    };
   }
 };